a 12 cm by 16 cm picture is mounted with border of uniform width on a rectangular frame. if the total area of the border is 288 cm2, what is the length of the side of the frame?

Answer 1

let l be the border width. Then the total area of the new picuture with border is..

Areatotal=areapicutre+areaborder.

areaborder=(12+2L)(16+2L)-12x16
288=24L+32L+4L^2

so solve for L, and the length of the fram is 16+2L

Answer 2

24