We have to find the length of a rectangular given that the
length is 12m more than the width and the numeric value of the area is four times that
of the perimeter.
Let the length be L adn the width be
W
The perimeter is 2*(L +
W)
The area is L*W
The length
is 12m more than the width, L = W + 12
Area = W*(W + 12) =
4* 2*(W + 12 + W)
=> W^2 + 12W = 8*(2W +
12)
=> W^2 + 12W = 16W +
96
=> W^2 - 4W - 96 =
0
=> W^2 - 12W + 8W - 96 =
0
=> W(W - 12) + 8(W - 12) =
0
=> W = 12 or -8
The
width cannot be negative, so we take width = 12
The length
= 12 + 12 = 24
The dimensions of the
rectangle are 12m W by 24m L.
No comments:
Post a Comment