If a rectangle With Width 49.872 inches and length 30.64 inches has an area that is 15 times the area of a certain square, which of the following is the closest approximation to the length, in inches, of a side of that square?
(A)5
(B)10
(C)15
(D)20
(E)25
The OA is B.
Should I multiply the numbers or can I work with approximations?
If a rectangle With Width 49.872 inches and length 30.64. .
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- EconomistGMATTutor
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Hello M7MBA.
The area of a rectangle is $$A_R=W\cdot L.$$
Let's take the aproximations $$W\approx50\ and\ L\approx30.$$ So, we will get $$A_R\approx50\cdot30\approx1500.$$
Now, the area of a square is $$A_S=a^2$$ where a is the length of each side. Now, we can set the equation $$A_R=15\cdot A_S\ <=>\ 1500\approx15\cdot a^2$$ $$a^2\approx100\ <=>a\approx10.$$
So, the answer is option B.
I hope this can help you.
I'm available if you'd like any follow up.
The area of a rectangle is $$A_R=W\cdot L.$$
Let's take the aproximations $$W\approx50\ and\ L\approx30.$$ So, we will get $$A_R\approx50\cdot30\approx1500.$$
Now, the area of a square is $$A_S=a^2$$ where a is the length of each side. Now, we can set the equation $$A_R=15\cdot A_S\ <=>\ 1500\approx15\cdot a^2$$ $$a^2\approx100\ <=>a\approx10.$$
So, the answer is option B.
I hope this can help you.
I'm available if you'd like any follow up.
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