A rectangular garden is 12 meters by 20 meters.

Question

A rectangular garden is 12 meters by 20 meters. Ts is to be doubled in area by adding a strip of uniform width to the top, right side and left side only. Find the width of the strip.

Answer 1

following calculation all assumes the top side is 20 meters and left&right sides are 12 meters

240 = 2(12x) + (20+2x)x = 24x + 20x + 2x^2

2x^2 + 44x - 240 = 0

x^2 + 22x - 120 = 0

x^2 + 22x + 121 = 120 + 121

(x+11)^2 = 241

x = -11 + sqr241 = about -11+15.5 = 4.5

2(12)(4.5) = 108

20+2(4.5) = 29

29(4.5) = 116+14.5= 130.5

108+130.5 = 238.5

x= width of strip, slightly larger than 4.5 meters