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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. isosceles triangle
Equal
At least 2 equal sides
61
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

2. acute angle
25
Less than 90
Opposite angles formed when two lines cross
8

3. obtuse angle
More than 90 but less than 180
More than 180
.5B*h
29

4. 30-60-90 right 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
Line segment from a vertex perpendicular to the base
Two angles totalling 90
.5B*h

5. 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
Line segment from a vertex perpendicular to the base
Two angles totalling 90
25

6. median
Angles less than 90/between 90 and 180
Line drawn from any angle of a triangle to the midpoint of the opposite side
S^2*sqrt(3)/4
SAS SSS AAA

7. angle bisector
17
C2=a2+b2
A line that bisects (halves) an angle in a triangle
Angles less than 90/between 90 and 180

8. area of equilateral triangle
29
26
S^2*sqrt(3)/4
SAS SSS ASA SAA HL

9. right angle
180
More than 180
90
17

10. 11-60-?
61
Angles less than 90/between 90 and 180
At least 2 equal sides
All equal sides

11. scalene 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
3 unequal sides
5
29

12. Following is true about isosceles triangles
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
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
8
180

13. similar triangles
61
SAS SSS AAA
C2=a2+b2
Equal

14. 9-40-?
Two angles totalling 90
13
41
Line segment from a vertex perpendicular to the base

15. vertical angles
Line drawn from any angle of a triangle to the midpoint of the opposite side
Opposite angles formed when two lines cross
Equal
Two angles totalling 180

16. equilateral triangle
A line that bisects (halves) an angle in a triangle
5
Opposite angles formed when two lines cross
All equal sides

17. 2 facts about triangles
Angles less than 90/between 90 and 180
Opposite angles formed when two lines cross
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa
26

18. 5-12-?
More than 90 but less than 180
SAS SSS AAA
More than 180
13

19. pythagorean theorem
41
A line that bisects (halves) an angle in a triangle
Less than 90
C2=a2+b2

20. congruent angles
Two angles totalling 90
29
Equal
.5B*h

21. altitute/height
Line segment from a vertex perpendicular to the base
All equal sides
More than 90 but less than 180
180

22. 6-8-?
8
SAS SSS AAA
17
Line drawn from any angle of a triangle to the midpoint of the opposite side

23. area of triangle
.5B*h
All equal sides
Two angles totalling 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

24. 8-15-?
3 unequal sides
Line segment from a vertex perpendicular to the base
17
15

25. straight angle
5
8
Extend one side of the triangle
180

26. supplementary angles
Two angles totalling 180
90
41
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

27. acute/obtuse triangle
5
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
Angles less than 90/between 90 and 180
A line that bisects (halves) an angle in a triangle

28. complementary angles
61
Two angles totalling 90
Equal
All equal sides

29. congruent triangles
Two angles totalling 90
More than 90 but less than 180
SAS SSS ASA SAA HL
All equal sides

30. 7-24-?
90
25
Opposite angles formed when two lines cross
Equal

31. 12-16-?
13
20
61
Line drawn from any angle of a triangle to the midpoint of the opposite side

32. 10-24-?
Line segment from a vertex perpendicular to the base
26
At least 2 equal sides
29

33. 9-12-?
90
15
SAS SSS AAA
25

34. exterior angle
A line that bisects (halves) an angle in a triangle
Two angles totalling 90
Extend one side of the triangle
29

35. reflex angle
SAS SSS ASA SAA HL
.5B*h
20
More than 180

36. 20-21-?
5
Two angles totalling 180
29
3 unequal sides

37. 3-4-?
5
Less than 90
20
The sum of any two sides muse be greater than the 3rd side - the largest side lies opposite the largest angle and vice versa