We know from the triangle sum theorem that the sum of the angles in a triangle is 180°. We can just add the angles and substitute to solve for ∠A.
∠A + ∠B + ∠C = 180
∠A + 58 + 90 = 180
∠A = 32
So, ∠A is 32°.
Next, we need to find CB and AB.
To find AB, we can use the sin of ∠B.
sin(∠B) = AC / AB
sin(58) = 13 / AB
AB = 13 / sin(58)
AB = 15.3
Then, we can just use the pythagorean theorem to solve for CB.
CB² + AC² = AB²
CB² + 13² = 15.3²
CB² + 169 = 234.09
CB² = 65.09
CB = 8.1
