Can someone walk me through these two questions plz

For number one, the answer is 225in^2
so you find the area of each and add it all together.
rectangular base:    5*7.5=37.5
Rectangular side:   5*10=50
Rectangular side:   5*12.5=62.5
Triangular side:      7.5*10*1/2=37.5
Triangular side:      7.5*10*1/2=37.5
add them all together:
225 in^2

And question 2:
Rectangular sides:  18*4.7=84.6
Rectangular sides:  18*4.7=84.6
Rectangular base:  18*5=90
Triangular sides:     5*4*1/2=10
Triangular sides:    5*4*1/2=10

Then add it all up!
84.6+84.6+90+10+10+90=279.2
279.2 in^2

The correct answer is: b