Questions on Geometry: Proofs in Geometry answered by real tutors!

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Question 62664: I Don't Understand Gemetry Proofs. Could You Send Me Information On How To Do Them?
Click here to see answer by checkley71(8403)

Question 62782: I am trying to write a proof for a Geometry problem and can not figure the proof out. Given triangle ABC is equilateral then prove m
Click here to see answer by jai_kos(139)

Question 63265: i dont know where this question should be posted Q. A certain isotope has a decay rate of-1.5% find its half life
thank you
Click here to see answer by uma(370)

Question 64046:
Make a Venn Diagram from the following information to answer questions 17 through 20:

25 students played soccer
4 boys played soccer and baseball
3 girls played soccer and baseball
10 boys played baseball
4 girls played baseball
9 students played tennis
3 boys played soccer and tennis
3 girls played soccer and tennis
3 boys played baseball and tennis
1 girl played baseball and tennis
1 boy played all three sports
1 girl played all three sports
12 girls played at least one of the three sports

19. How many students played just one of the three sports?
a)1
b)20
c)13
d)7
e)15
f) 5
20. How many girls played only baseball?
a)7
b)2
c)3
d)4
e)10
f )1

Click here to see answer by 303795(595)

Question 64044: I know I posted this wrong, but I hope some one can help me out with this:

Here is the Questions below:
Make a Venn Diagram from the following information to answer questions 17 through 20:

25 students played soccer
4 boys played soccer and baseball
3 girls played soccer and baseball
10 boys played baseball
4 girls played baseball
9 students played tennis
3 boys played soccer and tennis
3 girls played soccer and tennis
3 boys played baseball and tennis
1 girl played baseball and tennis
1 boy played all three sports
1 girl played all three sports
12 girls played at least one of the three sports

Hints on the diagram (highlight the following paragraph with your mouse to see them):
Notice that the counts don't make sense as they are, because they're all inclusive. The soccer count includes everyone who plays soccer, even the students in the soccer and baseball, soccer and tennis, and the all three sport counts. The count for soccer and baseball includes the two students who play soccer/baseball/tennis. So you'll need to correct from the inside outward...first subtract the boy and girl who play all three sports from all the other counts, then subtract the dual-sport counts from the single sport counts.
Put another way, this is like the gecko problem--the entire soccer circle including the soccer and baseball students and the soccer and tennis students and the students who play soccer and baseball and tennis, will add up to 25.
17. How many students played soccer, but not baseball or tennis?
a)4
b)25
c)12
d)6
e)14
f) 9
18. How many students played soccer and baseball, but not tennis?
a)5
b)10
c)3
d)4
e)7
f )13

Click here to see answer by 303795(595)

Question 65360: 16. 30 people are having lunch at my house. 16 of them want salads, 16 of them prefer pasta, and 11 of them want steak. 5 say they want to have both salad and steak, and of these, 3 want pasta as well. 5 want only steak, and 8 want only pasta. How many people want salad only?

a)3
b)4
c)16
d)7
e)11
f) 5

15. 500 students are enrolled in at least two of these three classes: Math, English, and History. 170 are enrolled in both Math and English, 150 are enrolled in both History and English, and 300 are enrolled in Math and History. How many of the 500 students are enrolled in all three?

a)300
b)330
c)200
d)120
e90
f 60

Click here to see answer by 303795(595)

Question 65362: 10. "A car can't take you to the moon" would be the
a)Converse
b)Countermove
c)Contrapositive
d)Counterexample
e)Counterpositive
f )Counter

11. The converse of the statement is:
a)If it is a small pinprick in the night sky then it is a star.
b)If it is not a star, then it is not a small pinprick in the night sky.
c)If it is not a small pinprick in the night sky, it is not a star.
d)Small pinpricks of light in the night sky might be satellites.
e)If it is a star, then it is a small pinprick of light in the night sky.
f) A really cool sneaker.

Click here to see answer by stanbon(57274)

Question 65768: Hello, I really can't figure this proof out, I've been trying for hours now and I just can't get it. Maybe you can help?

Prove: triangleTSW = triangleQPW
Given:

TQ bisects SP
SP bisects TQ
Click here to see answer by checkley71(8403)

Question 65764: Hi, I've been having some trouble with this proof that was assigned for homework. THANKS!!

Prove: triangleABC = triangleDEC

Given:

1. <1 = <6
BC = EC
Click here to see answer by checkley71(8403)

Question 65762: Hello,

I'm horrible at proofs, and this was on a homework assignment...Do you think you could help me?
THANKS!!
Just FYI, < is angle.

Prove: <3 = <2

1.Given

1. <1 = <4 , NA = TC

Click here to see answer by checkley71(8403)

Question 65766: Hi, I've been having trouble with this proof. Do you think you could help? THANKS!!

(FYI, // is parallel and _|_ is perpendicular)

Prove: NE = UR

Given:

MN = BU
MN // BU
NE _|_ MR
UR _|_ MR
Click here to see answer by checkley71(8403)

Question 65974: These two definationes are agreed upon:
a vertical lline is a line containing the center of the earth
a horizontal line is a line perpendicular to some vertical line
Which of the following would be true:
a. Could two horizontal lines be parallel
b. could two vertical lines be parallel
c. could two horzontal lines be perpendicular
d. could two vertical lines be perpendicular
e. could every horzontal line be a vertical line
f. could everty vertical line be a horizontal line
g. could a horizontal line be parallel to a vertical line
h. would every line be horizontal
Click here to see answer by uma(370)

Question 66824: If x^2 = 4 and y^2 = 9, compare: A.)x B.)y
Click here to see answer by checkley71(8403)

Question 66821: Write the quadratic equation with a lead coefficient of 1 whose roots are (-1/2) and (4/5).
Click here to see answer by checkley71(8403)

Question 68047: In the following problem a, b, c and d represent real numbers.

Prove: If a = b and c < d, then a + c < b + d

Click here to see answer by asdfg123(3)

Question 68261: Please help me solve the following proof:
The directions are:
Draw and label a diagram. List, in terms of the diagram, what is given and what is to be proved. Then write a proof.
The problem states:
If the vertex angle of one isosceles triangle is congruent to the vertex angle of another isosceles triangle, then the triangles are similar.
I made two triangles, triangle ABC and triangle DEF
I think the given is supposed to be: angle A is congruent to angle D
I think we need to prove: triangle ABC is similar to triangle DEF
What are the steps to the rest of this proof?
Click here to see answer by stanbon(57274)

Question 71699: Determine whether each statement is true or false. If it is false, provide a counterexample.
If a quadrilateral is equilateral, then it is equiangular.
Click here to see answer by stanbon(57274)

Question 71698: The Air Force Acedmy Cadet Chapel has 17 spires that point to the sky. Each spire is an isoscelea triangle with a 40 degrees vertex angle. Find the measures of the base angles.
Click here to see answer by stanbon(57274)

Question 73426: Please help i dont understand proofs:
Given: MI=LD
Prove:ML=ID
for reasons name the propety that makes the statement is true
Statements Reasons
MI=LD Given
IL=IL Reflexive
MI+IL=LD+IL I think addition
MI+IL=ML;LD+IL=ID I have no clue
ML=ID I think substitution
Click here to see answer by stanbon(57274)

Question 74750: Find the vertices of the ellipse X^2/36 + y^2/12 = 1
Click here to see answer by checkley75(3666)

Question 75052: Give the vertices of the hyperbola (x-12)^2/16 - (y-14)^2/25 = 1
I have choices for answers that are:
a.) V(12+-3,14)
b.) V(12+-4,14)
c.) V(12,14+-3)
d.) V(12,14+-5)
Click here to see answer by stanbon(57274)

Question 75141: Change the polar coordinates (4Sqrt2, 3pi/4), to rectangular coordinates.
Click here to see answer by funmath(2925)

Question 75812: Prove that if 2 medians of a triangle are congruent then the triangle is isosceles
Click here to see answer by Edwin McCravy(8887)

Question 75900: Select the best description for the curve given by the parametric equation
x = t-5, y = 2t-1, t in R.
Choices for answers are:
a.) a straight line with slope
b.) a straight line through the point (5,1)
c.) a parabola with vertex (-5,1)
d.) a circle centered at (5, -1)
Click here to see answer by stanbon(57274)

Question 75142: Change the polar coordinates (4Sqrt2, 3pi/4), to rectangular coordinates.
Click here to see answer by stanbon(57274)

Question 78974: How would I draw a venn dram.I got the problem but no idea how to do the rest. Helppp please thank you

on haloween the big pumpkin vitis the homes of all children, all grandmas, and all poets in tiwn. how many homes does he vitis , using these statistics. draw a venn diagram. 250+700+48=998 homes

children-- 800
grandmothers- 250
poets- 60
children and grandmothers...100
children and poets..10
grandmothers and poets...3
grandmothers and poets and children..1

Click here to see answer by mathdoc314(58)

Question 80777: I just had a question
Is it true that when constructing the median of a triangle, it is possible that the median may lie exterior to the triangle?
Click here to see answer by vertciel(183)

Question 81613: Write a proof argument for part (b) of the sufficient conditions for a parallelogram theorem: if both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram.
given: that the opposite sides are congruent.
prove: that the figure ABCD is a parallelogram
I drew in diagonals in the figure ABCD and labeled the point where they intersect E.
please help me solve this proof and provide the justifactions
this is very important. PLEASE try to get this back to me by the end of May 10th
thank you very much
Click here to see answer by scott8148(6628)

Question 84731: Please explain to me how to do this kind of proof:
Two spheres have radii a and b. Prove that the ratio of the areas is a^2 : b^2
Click here to see answer by PS(13)

Question 84999: If two lines intersect, their intersection is a________?
Click here to see answer by 303795(595)

Question 85377: Please help me with this problem
Use coordinate geometry to prove that quadrilateral PART with vertices P(-2,1), A(1,4), R(4,1) and T(1,-2) is a square
Click here to see answer by Edwin McCravy(8887)

Question 85400: 21. Given: Ray ST bisects Angle(<) RSV
m< RST= x+y
m< TSV= 2x-2y
m< RSV= 64 degrees
Find: x and y
It also gives a diagram before it which i will try and describe:
It is a pic of an angle split in two. the vertex is named s and the top ray has the endpoint called r and the middle endpoint it t and the bottom endpoint is v. I have tried to explain the diagram but i don't think i did it very well. oh, well.
if you go to this picture site and it has the picture but just different names for the points: http://education.yahoo.com/homework_help/math_help/solutionimages/minigeogt/1/1/1/minigeogt_1_1_1_13_1/f-37-49-oyo-1.gif
I'm sorry if you are asking what in the world is she talking about because it is understandable!
thank you if you find the answer!
-Athena
Click here to see answer by jim_thompson5910(28536)

Question 85376: I am really confused with this question, please help
Use a coordinate geometry to prove that the quadrilateral OPQR with vertices O(0,0), P(9,3),Q(9,8), and R(-3,4) is an isosceles trapezoid
Click here to see answer by venugopalramana(3286)

Question 86191: Theorem: The bisector of the vertex angle of an isosceles triangle is perpendicular to the base of the triangle.
Given:?
To prove:?
Analysis:?
I have to proof by writing a statement and the reason for that statement.
Thank you

Click here to see answer by scianci(186)

Question 86098: Given: lines AB, DE, and CF; line CG bisects angle BCF, and the line FG bisects angle CFE and i have to prove angle G is a right angle... if i could draw the picture it would be easier to explain it
Click here to see answer by 303795(595)

Question 85944: Calculate the monthly payment on a student loan of $40 000 borrowed at 9.8% for
5 years
INCLUDE a timeline
Click here to see answer by autumn Luv(1)

Question 87009: Give the reasons for the steps in the following proof. If 3x+(-1)=0, then x= 1/3
3x+(-1)=0
[3x+(-1)]+1= 0+1
3x+[(-1)+1]= 0+1
3x+0= 0+1
3x= 1
1/3(3x)= 1/3(1)
(1/3*3)x= 1/3*1
1*x= 1/3*1
x= 1/3
Click here to see answer by Edwin McCravy(8887)

Question 87463: Construct a truth table for
a. (p V q)-> (r ^ S)
b. (q-> ~p) V ( r<-> s)

Click here to see answer by stanbon(57274)

Question 87462: Determine whether the statement is a tautology, self-contradiction or neither
(p ^ ~q) -> q
Click here to see answer by jim_thompson5910(28536)

Question 88808: I've tried everything.

I need to give a detailed answer.

Please help.

Click here to see answer by bucky(2189)

Question 88958: __ __ __ __ Given: DABC; AB = CB; D is the midpoint of AB; E is the midpoint of BC Prove: ÐBDE = ÐBED

Click here to see answer by Edwin McCravy(8887)

Question 89799: x/3+x/6
_______
x/10
Click here to see answer by tutorcecilia(2152)

Question 90990: 1)can a regular polygon have interior angles of measure equal 25 degree. if so find the number of sides if not explain why?
no
2)ABCDE is a regular pentagon. line AE intersects line BC at point F. find the measure of angle AFB
Click here to see answer by stanbon(57274)

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