C + 20 - 13 = 100 im doing a test i need help

How to determine whether two known pairs of points are on the same line.

Ineed your ! i was to turn this into pond first thing i gotta do is outline the inside with this plastic how big should i cut the plastic the height: 10 1/2” the length: 40” the width: 12” me !

In δabc, m∠acb = 90°, cd ⊥ ab and m∠acd = 45°. find: a find cd, if bc = 3 in