Two angles that can be trisected with a straightedge and compass are a 90 angle and a _____ angle.A.75B.45C.90D.9

The correct answer is B. 45.

Here's why:

The only angles that can be trisected using a straightedge and compass are those that are multiples of 30 degrees. This is because the process of trisecting an angle involves dividing it into three equal parts, and the only way to do this with a straightedge and compass is if the angle is a multiple of 30 degrees.

A 90 degree angle can be trisected because 90 is a multiple of 30 (90 = 30 * 3).

A 45 degree angle can also be trisected because 45 is a multiple of 15, and 15 is half of 30. So, you can trisect a 45 degree angle by first bisecting it to get two 22.5 degree angles, and then trisecting each of those.

The other options, 75 and 9, are not multiples of 30 or any fraction of 30 that can be obtained using a straightedge and compass, so they cannot be trisected using these tools.