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

Tutors Answer Your Questions about Geometry proofs (FREE)

Question 704030: Given: line segment MO is the perpendicular bisector of line segment LN.
Prove: line segment MO bisects angle LMN
Click here to see answer by sachi(548)

Question 704504: How do you solve this false proof and what is the mistake in the proof?
a=1,b=1
a=b
a2=ab
a2+a2=a2+ab
2a2=a2+ab
2a2-2ab=a2-ab
2(a2-ab)= 1(a2-ab)
2=1
Click here to see answer by jim_thompson5910(35256)

Question 704815: Triangle HGJ
If angle H = 90 degrees, GJ is greater than GH.
How is GJ greater than GH? H = 90 degrees, and a triangle has to equal 180 degrees, I don't understand how it can be greater than and not less than.
Click here to see answer by KMST(5347)

Question 705653: given : AB is equal to EF, B is the midpoint of line AC, and E is the midpoint of line DF .
whats the justication for :
1. 2AB=2EF
2. AC=DF
3. line AC= line DF
Click here to see answer by geetha_rama(94)

Question 706004: given area of a triangle is 36 inches squared, base 3x inches, height 2x+2 inches, Prove: solve for x and find the base.
I totally don't get this or even know where to start!
Click here to see answer by ankor@dixie-net.com(22740)

Question 706085: Given: -4x = 2 < -10
prove: x>3
Click here to see answer by josgarithmetic(39799)

Question 709815: Is there an easy way to remember how to solve proofs? I'm having trouble remembering how to do them/
Click here to see answer by josgarithmetic(39799)

Question 711330: Prove the following theorem:
If the diagonals of a convex quadrilateral are perpendicular to each other, then the area of the quadrilateral equals one-half the product of the lengths of the diagonals
Click here to see answer by jim_thompson5910(35256)

Question 711757: Write a valid conclusion based on:

If <2 is acute, then <3 is obtuse.
If <3 is obtuse, then <4 is acute.
Click here to see answer by jim_thompson5910(35256)

Question 713776: How do you solve this equation?
Given: 3(x+4)-2(y+2)=3
Prove: y= 3/2x + 5/2
Click here to see answer by solver91311(24713)

Question 713804: PROVE: (Solve only one side until it matches the other)
[(sinA)/(cosA)][(1-sinA)/(cosA)]=1
Click here to see answer by solver91311(24713)

Question 715017: line CD bisects segment AB at point C. find AC if AB=56 feet.

Click here to see answer by KMST(5347)

Question 716179: Hi i'm stuck on the following question:
"For the set of positive rational numbers, show that division as the operation of combination is not associative. For this set is there any operation that is associative?"
Click here to see answer by solver91311(24713)

Question 716304: well, mi name is amayrani and i really dont know how to do a proof our teacher teach us "how to do it" but i really dont know how and we are having a test friday
Click here to see answer by solver91311(24713)

Question 716809: Given: m<1=m<2
Given: m<3=m<4
Prove: m
Click here to see answer by solver91311(24713)

Question 717236: I was given a triangle, Labeled ABC, which is bisected by line BD, to create two smaller triangles, ABD and DBC. Given: BD is the perpendicular bisector of AC. Prove: Line DB bisects Angle ABC
What am I missing? I think it falls apart the last two reasons. :(
Statements / Reasons
Step 1
Line BD is the perpendicular bisector of Line AC / Given
Step 2
Angle ADB and Angle BDC are right angles / Def. of perpendicular lines
Step 3
Angle ADB is congruent to Angle BDC / Rt angles are congruent
Step 4
Line AD is congruent to Line DC / Def. of bisector
Step 5
Line DB is congruent to Line DB / Reflexive ppty of congruence
Step 6
Triangle ABD is congruent to Triangle DBC / SAS
Step 7
Angle ABD is congruent to Angle DBC / CPCTC
Step 8
Line DB bisects Angle ABC / CPCTC

Click here to see answer by lynnlo(4176)

Question 717229: Given: Quadrilateral ABCD with segment AB congruent to segment CD, segment AD congruent to segment BC, and diagonal segment BD is drawn. Prove: angle ABC is congruent to angle ABD
Click here to see answer by lynnlo(4176)

Question 717668: Does the relation "is greater than" have a property of reflexive, symmetric or transitive property?

Click here to see answer by solver91311(24713)

Question 717747: Prove that if two circles are tangent externally, tangents to the circles
from a point on their common internal tangent are equal in length. I need help with this proof please.
Click here to see answer by mananth(16949)

Question 718539: Given: Quadrilateral ABCD; E, F, G and H are midpoints of AD, AB, BC, and CD respectively.
Proof: EFGH is a parallelogram.
Hint: Draw diagonal AC. Using triangle ABC and triangle ACD, prove line segment FG is parallel to line segment HE. Prove line segment FG is congruent to line segment HE. therefore EFGH is a parallelogram
(I Have The Picture Of The Quadrilateral give and everything if it would help more...) just email me for it to
pistilo-12z@live.com
Click here to see answer by mananth(16949)

Question 719290: How do we prove triangles similar when the given information only tells you about parallel lines?

Click here to see answer by solver91311(24713)

Question 720830: Hello there, I am hoping that you can help me with this geometry proof. I have been looking everywhere for an example, but have had no luck. I even checked geometry books out at our local library.
I believe that the problem is based on the Pythagorean Theorem Proof Using Similarity.
Given: ∆ ABC, AD bisects ∠BAC, and AE ≅ ED
Prove: AE/AC = BD/BC
The picture provided shows a triangle labeled ABC. AD bisects angle BAC. From point D there is another line that extends to the side of the triangle labeled AC, this point is labeled E. I am sorry that I am unable to attach a picture. Any help would be appreciated!

Click here to see answer by mananth(16949)

Question 722838: How do you prove that the midpoints of quadrilateral will form a parallelogram using a geometric proof?
Click here to see answer by solver91311(24713)

Question 723129: how would i do this .....line RS || segment AB, ∠1=∠2

Click here to see answer by stanbon(75887)

Question 723703: determine which of the following statements is a tautology
p ^ (p->q)
or
(p->q) <-> [(~p) v q]
Click here to see answer by solver91311(24713)

Question 723759: I need help with writing a formal proof for Corollary 2.4.4.
Click here to see answer by richwmiller(17219)

Question 724078: I am in need of help with proving the following:
GIVEN:
Line segment EG bisects angle DEF
Angle EDG is congruent to angle EFG
Prove: Triangle DGF is isosceles
Starting with the two given statments the next statements and reasons I have are:
Step 1
Line segment EG bisects angle DEF; Reason: Given
Step 2 Angle EDG is congruent to angle EFG; Reason: Given
Step 3
Triangle EDG is congruent to Triangle EFG;
Reason: ASA
Step 4 Line segment ED is congruent to line segment EF;
Reason: CPCTC
Step 5 Line segment EG is congruent to line segment EG;
Reason: Reflexive
Step 6
Triangle ABC is Isosceles;
Reason: Definition of Isosceles
Am I on the right track? Any help would be great. Thanks in advance!

Click here to see answer by KMST(5347)

Question 724533: i need the proof of law of cosines and sines
Click here to see answer by AnlytcPhil(1810)

Question 725785: Hello. I am having difficulty doing this paragraph proof. Can you guide me through the proof and help me solve it? thanks.
Angle ABC and Angle DBF are vertical. Prove that Angle ABD is congruent to Angle FBC
Click here to see answer by MathLover1(20855)

Question 725853: Write a two-column proof.
Here is the image for the proof:

Lines JM, KN, and LO all intersect at point P. measure of angle KPL = 30 and measure of angle JPL = 90. Prove the measure of angle NPM = 60.
1. Lines JM, KN, LO intersect at point P, measure of angle JPL = 30, measure of angle JPL = 90. | Given
I really don't know where to go from there.
Click here to see answer by mananth(16949)

Question 726111: write a two column proof. given: ABCD is an isosceles trapezoid,prove: triangle ABE is isosceles

Click here to see answer by fcabanski(1391)

Question 726807: What are all the reasons to proofs? Like is there a list? how do you now what to write as the reason
Click here to see answer by Edwin McCravy(20081)

Question 727553: Quadrilateral ABCD has vertices A( -6, -2 ), B( 0, -2), C( 4, 2), and D( 2, 6). Price that this is a trapezoid Explain your reasoning.
Click here to see answer by richwmiller(17219)

Question 727923: A rectangular parking lot has a length that is 5 meters more than twice its width. The area of the parking lot is 63 square meters. Find dimensions of parking lot
Click here to see answer by MathLover1(20855)

Question 729283: Suppose tanθ=-3/4 and π/2<θ<π. Evaluate the five remaining trigonometric functions of θ.
Click here to see answer by stanbon(75887)

Question 729414: If triangle ABC = 180 degrees and angle AEC = 72 degrees and segment BE= 20 and segment BE=DC what is the length of segment DE.

Click here to see answer by lynnlo(4176)

Question 730283: ABCD is a trapezium. The two diagonal AC and BD intersect in O. extended DA and CB intersect in P. prove that OP is the bisector of AB.
Click here to see answer by lynnlo(4176)

Question 731169: Point Q is the midpoint of PR. SQ is perpendicular to PR. name two right angles. Explain
Click here to see answer by josgarithmetic(39799)

Question 731869: Can you please help me on my homework? I'm not very good at proofs.
Given: K is the midpoint of HL and MJ. HL and MJ cross each other to create two triangles connecting at point K.
Prove: Triangle HJK is congruent to Triangle LMK.
Click here to see answer by fcabanski(1391)

Question 731826: Provide the reasons for the proof.
Given: m angle 1 = m angle 2
Prove: (line over)AC(up-side down T)(line over)BD
Statements:
a. m angle 1 = m angle 2
b. Angle 1 is supplementary to angle 2
c. m angle 1 + m angle 2= 180 degrees
d. m angle 1 + m angle 2 +180 degrees
2(m angle 1)= 180 degrees
e. m angle 1 = 90 degrees
f. angle 1 is a right angle
g.(line over)AC(up-side down T)(line over)BD
Reasons:
a. given
b. ?
c. ?
d. ?
e. ?
f. ?
g. ?
Click here to see answer by lynnlo(4176)

Question 732347: AC =~ DC and BC =~ CE. Prove Triangle ABC =~ to Triangle DEC.

Click here to see answer by lynnlo(4176)

Question 732347: AC =~ DC and BC =~ CE. Prove Triangle ABC =~ to Triangle DEC.

Click here to see answer by ohtheirony(35)

Question 732361: TWO PROOFS FOR THE SAME PICTURE.
1. Given: BD bisects AC, AB ≅ BC.
Prove: angle C ≅ angle A
2. Given: BD is perpendicular to AC, AB ≅ BC.
Prove: angle CBD ≅ angle ABD

Click here to see answer by lynnlo(4176)

Question 732383: TWO PROOFS FOR THE SAME PICTURE. Please explain.
1. Given: BD bisects AC, AB ≅ BC.
Prove: angle C ≅ angle A
2. Given: BD is perpendicular to AC, AB ≅ BC.
Prove: angle CBD ≅ angle ABD

Click here to see answer by MathLover1(20855)

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