A rectangle has a perimeter of 60 cm and an area of 210 cm^2. What are the dimensions of the rectangle?
Perimeter 2l + 2w = 60
area l * w = 210 w = 210/l sub this into the first equation
2l + 2 * 210/l = 60
2l^2 -60l + 420 = 0 Use quadratic fromula to find l & w = 15 + sqrt15 and 15 - sqrt 15 cm