Advanced MathEasy–MediumWidth of a rectangle from area and length
Advanced Math practice question
A rectangle has an area of x² + 3x square metres and a length of x + 3 metres, where x > 0. If x = 6, what is the rectangle's width, in metres?
Answer: 6
Width = (x² + 3x)/(x + 3) = x(x + 3)/(x + 3) = x. At x = 6, the width is 6. (Check: 54 ÷ 9 = 6.)
Common wrong answers
- If you answered 3
- 3 comes from keeping the wrong factor.
- If you answered 9
- 9 is the length at x = 6.
- If you answered 54
- 54 is the area at x = 6.
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