Cuáles son los valores de y en el siguiente sistema de ecuaciones

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality

Awindow has the shape of a rectangle with a semi circle at the top. find the approximate area of the window using the dimensions shown. 4ft by 8ft

Will mark brainliest! ( explain the answer too, it can be one sentence)