Please help me with this

Step-by-step explanation:

Both angles added together = 180 degrees. They both have a straight line as their base.

So let <ABC = x

Then <CBD = 3x      Add the two angles

x + 3x = 180              Combine

4x = 180                    Divide by 4

4x/4 = 180/4

x = 45

So 3x = 3*45 = 135

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation: