see the attached figure to better understand the problem
Step 1
Find the value of c
we know that
Applying the Pythagorean Theorem
we have
substitute the values in the formula
Step 2
Find the value of angle A (α)
we know that
in the right triangle ABC
Step 3
Find the angle B (β)
we know that
in the right triangle ABC
angle A and angle B are complementary angles
so
A+B=90
solve for B
B=90-A-------> B=90-60.48-----> B=29.52°
therefore
the answers are
a) the measure of side c is 580.36 mm
b) the measure of the angle α is 60.48°
c) the measure of the angle β is 29.52°