Question

WILL GIVE BRAINLIST... do i do 50 cosine 90 here? not sure.​

Answer 1

Answer:

x = 117.9°

Step-by-step explanation:

We require to find the size of the angle x

Given the law of cosines

c² = a² + b² - 2ab cosC

Rearrange to give cosC in terms of the sides

Add 2ab cosC to both sides

c² + 2ab cosC = a² + b² ( subtract c² from both sides )

2ab cosC = a² + b² - c² ( divide both sides by 2ab )

cosC = $\frac{a^2+b^2-c^2}{2ab}$

here a = 55, b = 50 and c = 90 and C = x

cosx = $\frac{55^2+50^2-90^2}{2(55)(50)}$

        = $\frac{3025+2500-8100}{5500}$

        = $\frac{-2575}{5500}$ ← - indicates angle is obtuse

x = $cos^{-1}$ ( $\frac{-2575}{5500}$ ) ≈ 117.9°

Answer 2

The answer should be : 117.9