A rectangle has a perimeter of 36 cm and its length is twice its width. What is its area?
Answer and explanation
Correct answer: B. 72 square cm, from a width of 6 cm and a length of 12 cm
- Step 1: Let the width be w. Then the length is 2w and 2(w + 2w) = 36, so 6w = 36 and w = 6. Step 2. Length = 12, area = 6 x 12 = 72. Answer: 72 square cm. Why not the others: 81 assumes equal sides; 48 uses a width that breaks the perimeter; 108 uses a length of 18 that is three times the width.
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