Question 808041: If the length of rectangle is twice as its width and perimeter is 42cms what is the length and breadth
Answer by MathTutor16(2)   (Show Source):
You can put this solution on YOUR website! Let us call the width of the rectangle "w" and the length of the rectangle "l".
The perimeter of the rectangle is the sum of all of its sides, which is the same as saying it is 2*width plus 2*length
We can set up a series of simultaneous equations:
2w+2l=42 ...1
l=2w ...2
Plugging in the second equation into the first:
2w+2*(2w)=42
2w+4w=42
w=7
Plugging back into the second equation:
l=2*(7)
l=14
Thus, the answer is l=14, w=7.
In these problems, it is always useful to check to make sure the answer makes sense. The problem says that the length of the rectangle rectangle is twice the width. Is it?
7*2=14, so our answer is correct.
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