Question

A dog pen in the shape of a rectangle is to be built using one wall of a house as a side. If 132 feet

Answer 1

This is a very poorly written question. im assuming the house wall is at least 130 ft since there is no information given about it.

each set of side lengths has three elements, the long side and the two short sides. we're asked to list all whole number possibilities so start anywhere, the two short sides being 1ft
(1 1 130). the long side has to be the difference of 132 and the length of both short sides.

the area is one of the short sides times the ling side, in the first case 1*130=130 sqft

continuing the list

(2 2 128) area=256
(3 3 126) area=378
(4 4 124) area=496
(5 5 122) area=610

the short sides increase by 1, the long side decreases by 2, the area gets bigger, but the difference between the areas are 4 less each time. dividing the first difference, 122, by 4 will give us a number to make a better guess from.

122÷4=30.5

so lets try

(30 30 72) area=2160

lets try 31 and see if that gives a smaller area

(31 31 70) area = 2170

(32 32 68) area =2176

(33 33 66) area = 2178

(34 34 64) area = 2176

so the area is decreasing now which means the maximum area is found when thw long side is 66 feet and the short sides are 33 feet.

as far as listing all possibilities, you see the pattern i started, i leave the rest to you