Question

Solve for x in the triangle
A 1.7
B 2.6
C 2.7
D 3.0

Answer 1

A

Explanation:

Given 2 sides and the included angle use the Cosine rule to solve for x

x² = 1.6² + 1.1² - (2 × 1.6 × 1.1 × cos78° )

= 2.56 + 1.21 - ( 3.52 × cos78° )

= 3.77 - 0.7318

= 3.0382

Take the square root of both sides

x =
`√(3.0382)` = 1.7 → A