SOLUTION: If the area of the rectangle is 645ft and legth is 12ft larger than the width find its length and its width. Please show step by step.

Algebra ->  Equations -> SOLUTION: If the area of the rectangle is 645ft and legth is 12ft larger than the width find its length and its width. Please show step by step.      Log On


   

Question 159702: If the area of the rectangle is 645ft and legth is 12ft larger than the width find its length and its width. Please show step by step.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
l=w+12
w(w+12)=645
w^2+12w-645=0
Using the quadratic equation:w+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ we get:
w=(-12+-sqrt[12^2-4*1*-645])/2*1
w=(-12+-sqrt[144+2580])/2
w=(-12+-sqrt[2724])/2
w=(-12+-52.19)/2
w=(-12+52.19)/2
w=40.19/2
w=20.095 answer for the width.
l=20.095+12=32.095 answer for the length.
Proof:
20.095*32.095=645
645=645