SOLUTION: A piece of cardboard is 25 cm taller than it is wide. It is mounted on a wall so that there is a 5 cm border on all sides. If the area of the border alone is 1350 cm^2, what are th

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: A piece of cardboard is 25 cm taller than it is wide. It is mounted on a wall so that there is a 5 cm border on all sides. If the area of the border alone is 1350 cm^2, what are th      Log On


   

Question 1111014: A piece of cardboard is 25 cm taller than it is wide. It is mounted on a wall so that there is a 5 cm border on all sides. If the area of the border alone is 1350 cm^2, what are the dimensions of the cardboard (not including the border)?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
The Cardboard
Width x
Tall x+25
Area of this carboard x%28x%2B25%29

Total area of border plus carboard
%28x%2B2%2A5%29%28x%2B25%2B2%2A5%29
%28x%2B10%29%28x%2B35%29

Area of JUST THE BORDER
highlight_green%28%28x%2B10%29%28x%2B35%29-x%28x%2B25%29=1350%29
-
x%5E2%2B45x%2B350-x%5E2-25x=1350
45x%2B350-25x=1350
20x=1350-350
20x=1000
2x=100
highlight%28x=50%29------width
-
Height is highlight%2875%29.