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GRE Math: Angles And Triangles

Instructions:

Answer 37 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Following is true about isosceles triangles
Equal
The base may be equal - greater or less than any other side - the legs are equal - angle across base is the vertex angle (+><) - base angles are equal
Line segment from a vertex perpendicular to the base
180

2. 15-20-?
The base may be equal - greater or less than any other side - the legs are equal - angle across base is the vertex angle (+><) - base angles are equal
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa
20
25

3. 6-8-?
3 unequal sides
29
15
8

4. congruent angles
Equal
Two angles totalling 180
61
Less than 90

5. complementary angles
More than 90 but less than 180
Two angles totalling 90
SAS SSS ASA SAA HL
Get shorter leg first - shorter leg is half hyp - to find short leg given hyp - div by 2 - to find hyp given short leg - *2 - find short leg given hyp - div by sqrt3 - find long leg given short leg - *sqrt3

6. 11-60-?
Angles less than 90/between 90 and 180
Line segment from a vertex perpendicular to the base
Equal
61

7. 2 facts about triangles
Two angles totalling 90
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa
At least 2 equal sides
All equal sides

8. 30-60-90 right triangle
20
13
All equal sides
Get shorter leg first - shorter leg is half hyp - to find short leg given hyp - div by 2 - to find hyp given short leg - *2 - find short leg given hyp - div by sqrt3 - find long leg given short leg - *sqrt3

9. 5-12-?
13
More than 90 but less than 180
8
Two angles totalling 90

10. 7-24-?
25
26
Less than 90
61

11. angle bisector
SAS SSS ASA SAA HL
17
The base may be equal - greater or less than any other side - the legs are equal - angle across base is the vertex angle (+><) - base angles are equal
A line that bisects (halves) an angle in a triangle

12. 9-12-?
Two angles totalling 180
41
.5B*h
15

13. exterior angle
20
3 unequal sides
180
Extend one side of the triangle

14. 10-24-?
More than 180
25
26
Equal

15. obtuse angle
Equal
All equal sides
C2=a2+b2
More than 90 but less than 180

16. median
Line drawn from any angle of a triangle to the midpoint of the opposite side
29
13
3 unequal sides

17. 8-15-?
8
S^2*sqrt(3)/4
17
20

18. equilateral triangle
Angles less than 90/between 90 and 180
All equal sides
Less than 90
Two angles totalling 90

19. right angle
29
90
All equal sides
61

20. 9-40-?
41
More than 180
180
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa

21. acute/obtuse triangle
At least 2 equal sides
Angles less than 90/between 90 and 180
29
Two angles totalling 90

22. 12-16-?
20
S^2*sqrt(3)/4
41
SAS SSS AAA

23. reflex angle
17
25
5
More than 180

24. scalene triangle
Opposite angles formed when two lines cross
Two angles totalling 180
Angles less than 90/between 90 and 180
3 unequal sides

25. area of triangle
S^2*sqrt(3)/4
.5B*h
Extend one side of the triangle
The base may be equal - greater or less than any other side - the legs are equal - angle across base is the vertex angle (+><) - base angles are equal

26. altitute/height
Line segment from a vertex perpendicular to the base
26
More than 180
3 unequal sides

27. similar triangles
SAS SSS AAA
The base may be equal - greater or less than any other side - the legs are equal - angle across base is the vertex angle (+><) - base angles are equal
Equal
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa

28. acute angle
Less than 90
8
Two angles totalling 90
Equal

29. isosceles triangle
Equal
25
At least 2 equal sides
Extend one side of the triangle

30. supplementary angles
Two angles totalling 180
More than 90 but less than 180
41
61

31. straight angle
More than 180
61
180
C2=a2+b2

32. area of equilateral triangle
Get shorter leg first - shorter leg is half hyp - to find short leg given hyp - div by 2 - to find hyp given short leg - *2 - find short leg given hyp - div by sqrt3 - find long leg given short leg - *sqrt3
S^2*sqrt(3)/4
5
29

33. 20-21-?
180
SAS SSS AAA
29
More than 180

34. pythagorean theorem
Opposite angles formed when two lines cross
C2=a2+b2
Angles less than 90/between 90 and 180
Two angles totalling 90

35. congruent triangles
Line segment from a vertex perpendicular to the base
17
SAS SSS ASA SAA HL
8

36. 3-4-?
Less than 90
5
At least 2 equal sides
41

37. vertical angles
More than 90 but less than 180
Less than 90
25
Opposite angles formed when two lines cross