Answer:
Part 1)

Part 2)

Part 3)

Explanation:
step 1
Find the measure of angle A
Applying the law of cosines

we have

substitute

Solve for A



using a calculator

step 2
Find the measure of angle B
Applying the law of cosines

we have

substitute

Solve for A



using a calculator

step 3
Find the measure of angle C
we know that
The sum of the interior angles in any triangle must be equal to 180 degrees
so

we have


substitute


