I suck at math. △ABC△ABC is similar to △XYZ△XYZ by the AA Similarity PostulateAA Similarity Postulate . The measure of ∠A∠A is 39º and the measure of ∠C∠C is 24º. What is m∠Ym∠Y?

If △ABC is similar to △XYZ, the angles have the same degree measure.

Since m∠A is 39° and m∠C is 24°, and the total measure of the inner angles is;

(n - 2) 180 ° = (3 - 2) 180° = 180°,

180 ° = m∠A + m∠B + m∠C

180 ° = m∠B + 39° + 24°

m∠B = 117°

But because △ABC is similar to △XYZ, m∠B = m∠Y;

m∠B = m∠Y = 117°

180 degrees in a triangle. subtract the 2 know angles to get the third.

180-39-24=117