A shape that is 3-d is
Form
Value
Shape
Variety

Form.

Explanation:

Form can be defined as an element of art and it has three-dimensions, height width and depth, and are usually enclosed in space.

This ultimately implies that, height (length), width (breadth) and depth are the three dimensional parameters that makes up a form.

Form as a an element of art, principle of design and media can either be geometric or free-form.

Hence, a shape that is 3-dimensional is known as form.

it stands for behind the scenes

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