The dimensions of a rectangle are StartRoot 50 a cubed b squared EndRoot and StartRoot 200 a cubed EndRoot. A student found the perimeter as follows: 2 StartRoot 50 a cubed b squared EndRoot + StartRoot 200 a cubed EndRoot = 2 times 5 a b StartRoot 2 a EndRoot times 10 a StartRoot 2 a EndRoot. = 10 a b StartRoot 2 a EndRoot + 20 a StartRoot 2 a EndRoot. = 30 a b StartRoot 2 a EndRoot.
What is the student’s error?
The student should not have multiplied each expression by two.
