Question

PLEASE HELP ASAP!!!! I GIVE A BRAINLIEST TO THE RIGHT ANSWER!!!!

Answer 1

Use cosine law to solve the problem. See image attached.
What we're looking for is the length of side A (a side which is opposite with angle A).

This is the formula of cosine law
A² = B² + C² - 2BC cos A

Input the numbers
A² = 75² + 90² - 2(75)(90) cos 85°
A = $\sqrt{75^{2}+90^{2}-2(75)(90)cos85^{0}}$
A = $\sqrt{90^{2}+75^{2}-2(90)(75)cos85^{0}}$