Question

(05.05 MC) what are the measures of angles a, b and c? explain your answer​

Answer 1

Check the picture below.

∡a has a vertical angle sibling of 40°, and vertical angles are always congruent.

∡b is the 3rd angle in a triangle, the other two are 40° and 90°, recall all interior angles in a triangle add up to 180°.

∡c is a linear angle, namely an angle on the same flat-line as another, and linear angles always add up to 180°.