# Weird question???

• May 24th 2010, 07:33 PM
GAVREED2
Weird question???
This question is in my engineering course and i am having lots of trouble with it. Mainly because i thought you could only find measurements for the length and breadth of rectangle if you are given the perimeter and area, however this question only gives you the perimeter. HERE'S THE QUESTION ANYWAY.

1) A rectangle has a perimeter of 26m.
a)Express its length(l) in terms of the breadth(b)?
b) Write an expression for the area of the rectangle in terms of (b) only?
c) Find the breadth of this rectangle if its area is 38metres^2
• May 24th 2010, 07:55 PM
harish21
Quote:

Originally Posted by GAVREED2
This question is in my engineering course and i am having lots of trouble with it. Mainly because i thought you could only find measurements for the length and breadth of rectangle if you are given the perimeter and area, however this question only gives you the perimeter. HERE'S THE QUESTION ANYWAY.

1) A rectangle has a perimeter of 26m.
a)Express its length(l) in terms of the breadth(b)?
b) Write an expression for the area of the rectangle in terms of (b) only?
c) Find the breadth of this rectangle if its area is 38metres^2

If $l$ is the length and $b$ is the breadth of the rectangle, then its perimeter is $P=2(l+b)$

so you have: $2(l+b)=26$

(a) $2(l+b)=26 \implies (l+b)=13 \implies l = 13-b$

(b) $\mbox{Area} = l \times b = (13-b) b$

(c) $(13-b)b = 38$ solve for b
• May 24th 2010, 08:18 PM
GAVREED2
Thanks!
Cheers mate! I get the question now lol...actually fairly simple.