Download 4.6 isosceles and equilateral triangle assignment

Geo 4.6 Isosceles and Equilateral Triangles
Name __________________________
Learning Objective: After this lesson, you should be able to successfully use theorem about isosceles and
equilateral triangles to find missing parts of triangles.
Standard: G.SRT.5 Use congruence and similarity criteria for triangles to solve problems and to prove
relationships in geometric figures.
G.CO.7 Use the definition of congruence in terms of rigid motions to show that two triangles are
congruent if and only if corresponding pairs of sides and corresponding pairs of angles are
congruent.
G.CO.8 Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow from the
definition of congruence in terms of rigid motions.
G.CO.10 Prove theorems about triangles.
Find the value of the variable by writing an equation and showing all work.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. If AC  AD , name two congruent angles.
11. If BE  BC , name two congruent angles.
12. If EBA  EAB , name two congruent segments.
13. If CED  CDE, name two congruent segments.
Find each measure.
14. mABC
15. mEDF
Find each measure. mKMH = 50
16. mKML
17. mHMG
18. mGHM
19. If mHJM = 145, find mMHJ
20. If mG = 67, find mGHM
21. SPORTS A pennant for the sports teams at Lincoln High School is
in the shape of an isosceles triangle. If the measure of the vertex angle
is 18, find the measure of each base angle.
Find each measure.
22. mBAC
23. mSRT
Answers: 1. 4x + 40 = 180, x = 35
7. 2(2x + 3) + 90 = 180, x = 21
15. 70
17. 70
19. 17.5
24. TR
25. CB
3. 14x + 12 = 180, x = 12
9. 6x + 12 + 90 = 180, x = 13
21. 81 and 81
23. 65
25. 3
5. 4x – 4 = 3x + 8, x = 12
11. BEC  ECB
13. CE  CD