What is the missing reason for the 5th step in the proof below A. Simplification of equation from previous step B. Definition of complementary angles C. Substitution D. Definition of a linear pair​

Your answer would be ahere is how: perimeter is how long all the sides are. in a rectangle, there are two sets of parallel sides. so, to find this, we would to the following.(15x2)+(4x2)30+838if you have questions ask! and mark me brainliest! i really wanna level up : 3

Hold on lemme do the work