Set 2: Triangles (Beginner)

**Choice D is the best answer.** Third angle = 180 - 78 - 45 = 57 degrees

Explanation

Answer: D

PROBLEM

A triangle has angles of 78 degrees and 45 degrees. What is the third angle?

A.

54

B.

59

C.

58

D.

57

✓ Correct

Detailed Explanation

Choice D is the best answer. Third angle = 180 - 78 - 45 = 57 degrees

Why others are wrong:

A: 54 is incorrect because it does not satisfy the equation.

B: 59 is incorrect because it does not satisfy the equation.

C: 58 is incorrect because it does not satisfy the equation.