Please tell how to solve these kind of problems. Especially 9. (I'm CLUELESS)

Given: m∠ adb = m∠cdb ad ≅ dc prove: m∠ bac = m∠bca lol

Pyotr tchaikovsky sporting goods operates on a 45% overhead based on the selling price, which results in an overhead of $65.34 on the newest version of an air hockey game set. if the air hockey game set costs pyotr tchaikovsky sports $49.32, find the selling price, the markup, and the net profit.

The graph shows the charges for a health club in a month. make a function table for the input-output values. writes an equation that can be used to find the total charge y for the number of x classes