length = 1/2 w+9
perimeter= 60 =2(l+w)
substitute in for length
60 = 2(1/2 w +9 +w)
60 = 2 (3/2 w +9)
distribute
60 = 3w + 18
subtract 18 from each side
42 = 3w
divide by 3 on each side
14 = w
length = 1/2 w + 9
length = 1/2 (14) +9
7 + 9
16cm
The model hight for the door will be 27 centimeters
First, you've got to figure out the value of the radius so divide the diameter by two. Then, you'll want to find the area of the base or pi times radius squared.
(3.14x3^2)x9=V
After doing the math your answer comes out to 254.34 cubic feet or feet^3