Geometry Questions and Solutions8) If the length of a rectangle is twice the width of it, what is the length if the perimeter is 30? Perimeter is the sum of the sides of shape Perimeter for rectangle "p" = 2 (length "l" + width "w") to cover all 4 sides. Since "l" is twice "w", then l = 2w p = 2 (l + w) 30 = 2 (2w + w)
30 = 2 (3w) We have to make "w" subject of formula, so we first move 2 to the other side, then 3. When you move to the other side, addition becomes subtraction, multiplication becomes division, and vice versa. 30/2 = 3w (2 was a multiplication at the other side) 15 = 3w 15/3 = w (3 multiplied w at the other side) 5 = w If the width is 5, then the length must be 10.

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