Answer:
- length: 30 cm
- width: 12 cm
Explanation:
The perimeter is twice the sum of the lengths of adjacent sides. If we let w represent the width, then 2.5w can represent the length. The perimeter (in centimeters) is ...
P = 2(L +W)
84 = 2(2.5w +w) . . . . . substitute known values
84 = 7w . . . . . . . . . . . . simplify
12 = w . . . . . . . . . . . . . .divide by 7
L = 2.5w = 2.5×12 = 30
The width is 12 cm; the length is 30 cm.