Hi, 

*Note;  Key to these is assigning a variable.

Let x represent the height, then the width would be (x -12)

x + x + (x -12) + (x -12) = 200ft

x = 56ft, is the height and the width 44ft  (56-12)

checking our answer

2*56ft + 2* 44ft = 200ft

112ft + 88ft = 200 ft



Second Set up is:

Let x represent the width, then the length would be 7x

Let You take it from there. 

RELATED QUESTIONS

a rectangle whose perimeter is 176 feet, has a length that is six feet longer than its... (answered by Greenfinch)

A rectangle has a length that is 3 feet longer than is width. Its perimeter is 26 feet.... (answered by pmesler)

A rectangle is 5 feet longer than twice
its width. If the rectangle has a perimeter of... (answered by jorel1380,chriswen)

A rectangle's width is six times its length. The perimeter of the rectangle is two... (answered by vleith)

1. A rectangle whose perimeter is 46 feet has a length that is 8 feet longer than its... (answered by nycsub_teacher)

A rectangle has a length that is 6 feet more than the width. Its perimeter is 100 feet.... (answered by hamsanash1981@gmail.com)

A rectangle has a length that is 6 feet more than the width. Its perimeter is 100 feet.... (answered by ewatrrr)

The length of a rectangle is 9 feet less than twice its width. The perimeter is 54 feet.... (answered by stanbon)

a perimeter of a rectangle is 78 feet. its length is seven feet more than its width. what  (answered by sachi)