Question 22
Triangles and QuadrilateralsFind the length XZ in the triangle above.
- A.√7 m
- B.√6 m
- C.√5 m
- D.√3 m
Show the answer and explanation
Answer: A (√7 m)
Explanation
By the cosine rule with XY = 2 m, YZ = 1 m and ∠Y = 120°: XZ² = 4 + 1 − 2(2)(1)cos 120° = 5 + 2 = 7, so XZ = √7 m.