If you know the total length, and the length of one part, and you're trying to find the other part, just subtract.
81-53=28
bc=28
Surface area of cylinder = 2πrh + 2πr^2
SA for cylinder A = 2π x 2 x 2 + 2π x (2)^2 = 8π + 8π = 16π
SA for cylinder B = 2π x 2 x 4 + 2π x (2)^2 = 16π + 8π = 24π
We need to find the value of the hypotenuse in order to solve this problem.
12^2+4^2=H^2
Therefore:
H=√(144+16)
H=4√10
Now:
sin(G)=O/H=4/(4√10)
=1/(√10)
=(√10)/10
L=w+9
p=2w+2l
p=2w+2*(w+9)
p=2w+2w+2*9
p=4w+18
4w+18=38
4w=38-18
4w=20
w=20:4
w=5 in
l=5+9=14 in