AlgebraEasy–MediumArea of a rectangle from perimeter and a difference
Algebra practice question
A rectangle has a perimeter of 40 units, and its length is 4 units more than its width. What is the area of the rectangle, in square units?
Answer: 96
With width w and length w + 4, 2(2w + 4) = 40 gives w = 8, so the length is 12 and the area is 96.
Common wrong answers
- If you answered 8
- 8 is the width.
- If you answered 20
- 20 is the sum of the length and width.
- If you answered 100
- 100 uses 10 by 10, ignoring the difference.
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