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

Tutors Answer Your Questions about Geometry proofs (FREE)

Question 384775: use indirect reasoning to explain the statement true.......
If an isoscles triangle is obtuse then the obtuse angle is the vertex angle.

Click here to see answer by armstrkl(28)

Question 385226: Given: m is the perpendicular bisector of line AB. P is on m.
To Prove: PA=PB
Click here to see answer by richard1234(5390)

Question 385669: how to solve this proof
given: segment ab is congruent to segment cb, angle a is congruent to angle c, and segment db bisects angle abc
prove: segment ad is congruent to segment cd
Click here to see answer by richard1234(5390)

Question 386097: angle ABD is a right angle .... what would be the reason or theorem for that?
Click here to see answer by Alan3354(30958)

Question 386238: write the algebraric expression for each line y=mx+b
Line b, m=-1, passes through(3,3)
Click here to see answer by rfer(12644)

Question 386370: whats the complement and supplement of 55, 68, 13, 27, 82 and 34 degrees
Click here to see answer by richard1234(5390)

Question 386415: can you explain the final proof of a statement in angles, and triangles? for example: SSS,SAS,AAS?
Click here to see answer by richard1234(5390)

Question 386579: Can you give me a couple of tough proofs to study from for my exam tomorrow? or a link to a good website
Click here to see answer by richard1234(5390)

Question 386789: Prove that if in the triangle ABC with right angle at A, there is a point D on CB so that AC equals AD equals DB, then angleB equals 30 degrees.
This has completely stumped me.
Click here to see answer by richard1234(5390)

Question 387008: Prove lines containing the altitudes of any triangle are concurrent
Click here to see answer by richard1234(5390)

Question 387117: What are all of the Theorms, definitions, ect. for proofs, along with examples?
Click here to see answer by richard1234(5390)

Question 387192: Write an indirect proof for,
Given: n squared is even
Prove: n squared is divisible by 4

Click here to see answer by jim_thompson5910(28476)

Question 387145: do the diagonals in an isosceles trapezoid form perpendicular lines??
Click here to see answer by scott8148(6628)

Question 387958: Please help me with this problem. If a median is also an altitude of a triangle, prove the triangle is isosceles.
Click here to see answer by scott8148(6628)

Question 387584: Okay whats a reason
Click here to see answer by mdenny(8)

Question 388119: What is the contrapositive of the following conditional?
If a triangle is equilateral, it is equiangular.

Click here to see answer by avani(25)

Question 388120: What is the converse of the following conditional?
If two segments are congruent, then they have equal measures.

Click here to see answer by avani(25)

Question 388121: What is the converse of the following theorem?
If a point is on the bisector of an angle, it is equidistant from the sides of the angle.

Click here to see answer by avani(25)

Question 388117: Given: ∠ABD≅∠DBC; B is the midpoint of AC
Prove: ΔABD≅ΔCBD
Which postulate proves these triangles congruent?

Click here to see answer by kingme18(98)

Question 388289: How do I prove the theorem "Through a given point of a given line there is only one plane perpendicular to the line"?
Click here to see answer by Alan3354(30958)

Question 388287: How do I prove the theorem that states "Through a given point of a given line there passes a plane perpendicular to the given line"?
Click here to see answer by Alan3354(30958)

Question 388257: I am trying to prove "The opposite sides of a parallelogram are congruent". Can you help me?
Click here to see answer by solver91311(16868)

Question 388179: (Similar figure, only use one)
Give the reasons for the following proof
Given: angle FMR is congruent to angle FMR
angle 1 is congruent to angle 3
Prove: angle 2 is congruent to angle 4

Statement--------------------------------------------------------------Reason
1. angle FMR is congruent to angle FMR;angle 1 is congruent to angle 3|1. Given
2. m angle FMR= m angle FRM-------------------------------------------|2. Reflexive prop.
3. m angle FMR= m angle 1+m angle 2; m angle FMR= m angle 3+m angle 4-|3. __?__
4. m angle 1+ m angle1= m angle 3+ m angle 4--------------------------|4. __?__
5. m angle 1=m angle 3------------------------------------------------|5. __?__
6. m angle 1+ m angle 2= m angle 1+ m angle 4-------------------------|6. substitution
7. m angle 2= m angle 4-----------------------------------------------|7. __?__
8. angle 2= angle 4---------------------------------------------------|8. __?__
Click here to see answer by solver91311(16868)

Question 388389: Question came up in my vectors/calculus course.
If triangle ABC is an isosceles triangle in which AB = AC. Prove that the median AM is perpendicular to BC.

Thanks for the help ^^
Click here to see answer by richard1234(5390)

Question 388387: Okay hpw do you plan out proofs?

Click here to see answer by richard1234(5390)

Question 388477: Through a given point of a given line there is only one plane perpendicular to the line
Click here to see answer by Alan3354(30958)

Question 388113: Given: WX≅WZ; XW⊥XY; WZ⊥ZY
Prove: WY bisects ∠XYZ
Statement:
1. XW⊥XY; WZ⊥ZY (given)
2. ∠YXW and ∠WZY are right angles
3. WX≅WZ (given)
4. YW≅YW
5. ΔXYW≅ΔZYW (HL theorem)
6. ∠1≅∠2
7. m∠1=m∠2 (definition of congruent angles)
8. WY bisects ∠XYZ
what is the correct reason for statement 2?

Click here to see answer by richard1234(5390)

Question 387598: statement: angle 1 is a right angle, what is the reason?
Click here to see answer by richard1234(5390)

Question 388114: Given: WX≅WZ; XW⊥XY; WZ⊥ZY
Prove: WY bisects ∠XYZ
Statement:
1. XW⊥XY; WZ⊥ZY (given)
2. ∠YXW and ∠WZY are right angles
3. WX≅WZ (given)
4. YW≅YW
5. ΔXYW≅ΔZYW (HL theorem)
6. ∠1≅∠2
7. m∠1=m∠2 (definition of congruent angles)
8. WY bisects ∠XYZ
Choose the correct reason for statement 4?

Click here to see answer by richard1234(5390)

Question 388372: Given: ABCD is arhombus.
prove:AC bisects angle BAD and angel BCD.
Click here to see answer by robertb(4012)

Question 388592: What is it called when you have 2 parallel lines and one has a perpendicular to another line? The figure that I'm using looks like this:
It's for a proof.
Given: j||k, m is perpendicular to j
Prove: m is perpendicular to k
Statements------------------------------------------Reason
1. j||k---------------------------------------------1. Given
2. m is perpendicular to j--------------------------2. Given
3. angle 1 is congruent to angle 2------------------3. Alternate interior angles
4. m of angle 1=90----------------------------------4. Definition of perpendicular lines
5. m of angle 2=90----------------------------------5. Definition of perpendicular lines
6. m is perpendicular to k--------------------------6. __?__
Click here to see answer by jsmallt9(3296)

Question 388724: Given: BC= CD, AB= DE
Prove: AC= CE
Click here to see answer by Alan3354(30958)

Question 388724: Given: BC= CD, AB= DE
Prove: AC= CE
Click here to see answer by richard1234(5390)

Question 388745: given: PO is purpindiculr to QR; PS is purpindiculr to SR; <1=<4
prove: <2=<5
Click here to see answer by Alan3354(30958)

Question 388772: Provide a counter-example to dispute side side angle (ssa) as a sufficient shortcut to determine congruency between triangles.
Click here to see answer by Edwin McCravy(8879)

Question 388256: a tri colored flag is made out of a rectangle piece of cloth whose corners are labeled a b c d the colored regions are separated by two line segments line segment bm and line segment cm that meet at pt m is the mid point of line segment aD prove the segments that separate the regiond will always be equal

Click here to see answer by robertb(4012)

Question 388887: Similar. A is angle 1, the angle next to it is angle 2, then angle 4 and B is angle 5, the top is angle 3.

Given: angle 1 is congruent to angle 5
Prove: angle 2 is congruent to angle 4

Statement---------------------------------------Reason
1. angle 1 is congruent to angle 5-----------------1. Given
2. m angle 1+ m angle 2= 180------------------------2. Linear pair= 180
3. m angle 4+ m angle 5= 180------------------------3. Linear pair= 180
4. m angle 1+ m angle 2= m angle 4+ m angle 5--------4. ?
5. m angle 2 is congruent to m angle 4-----------------5. ?
6. angle 2 is congruent to angle 4------------------6. Definition of Congruency
Click here to see answer by vampirewitchreine(6)

Question 388172: AB intersect at e. M of ACE =11y M of CEB=5x-2y and M of BED =5x+2y Find M of AED
Click here to see answer by jerryguo41(162)

Question 388883: Sorry, I couldn't find a better picture. Just look at the bold triangle part, ignore the dotted lines.

PR is line HV, AC is line TU and Q is point R. Ignore all numbers on the image. H is angle 7, V us angle 6, and U is angle 8.

Given: HV||TU, angle 6 is congruent to angle 7
Prove: Angle 7 is congruent to angle 8.
Statement------------------------------Reason
1. HV||TU------------------------------1. Given
2. Angle 6 is congruent to angle 7-----2. Given
3. Angle 6 is congruent to angle 8-----3. Corresponding angles
4. Angle 7 is congruent to angle 8-----4. __?__
Click here to see answer by jerryguo41(162)

Question 388769: How to write a two column proof to show that the diagonals of a rhombus bisect the angles of the rhombus.
Click here to see answer by ewatrrr(10682)

Question 388770: How to write a 2 column proof to show that an angle bisector of the vertex of an isosceles triangle is also an altitude.
Click here to see answer by richard1234(5390)

Question 387597: statement: angle 1= 90 degrees, what is the reason?
Click here to see answer by richard1234(5390)

Question 388888: Similar. A is angle 1, the angle next to it is angle 2, then angle 4 and B is angle 5, the top is angle 3.

Given: angle 1 is congruent to angle 5
Prove: angle 2 is congruent to angle 4

Statement---------------------------------------Reason
1. angle 1 is congruent to angle 5-----------------1. Given
2. m angle 1+ m angle 2= 180------------------------2. Linear pair= 180
3. m angle 4+ m angle 5= 180------------------------3. Linear pair= 180
4. m angle 1+ m angle 2= m angle 4+ m angle 5--------4. ?
5. m angle 2 is congruent to m angle 4-----------------5. ?
6. angle 2 is congruent to angle 4------------------6. Definition of Congruency
Click here to see answer by jerryguo41(162)

Question 388932: prove that if the diagonals of a parallelogram are perpendicular, then the parallelogram is a rhombus.
Click here to see answer by robertb(4012)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890