Question

The button on Sam's calculator that calculates the sine of an angle is broken.

Explain how to solve for x without using the sine ratio. Round x to the nearest tenth.

Answer 1

tan 18 = opposite side/adjacent side

0.3249 = 4/adjacent side

and adjacent side = 4/0.3249 = 12.31

Now let's apply Pythagoras to find x

4² + 12.31² = x²
16 + 151.55 = x²   and x² = 167.55 
Then x = √167.55 and x = 12.94 ≈ 13