How do I start painting?

Start by painting the background first.

Explanation:

It will be very hard to constantly do small parts of the background if you don't do it first, therefore, if you paint the background first, you can constantly overlap more and more until you get your final picture.

perimeter = 2l +2w, divide total perimeter by 2 for total length of 1 side and 1 width

172/2 = 86 (  total for 1 side and 1 width)

86-24 = 62 (since length is 24 ft longer subtract 24 then divide by 2 for width)

62/2 = 31

width = 31 feet

length = 31 +24 = 55 feet

check: 31*2 = 62, 55*2 = 110,  110+62 = 172