The value of \(\frac{(4.2)^3}{(2.1)^2}\) is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 16.8
4.2 is twice 2.1, so writing the numerator in terms of 2.1 lets most of the powers cancel.
Writing 4.2 as \(2\times2.1\): \((4.2)^3=(2\times2.1)^3=8\times(2.1)^3\)
Two of the three factors of 2.1 cancel with the denominator: \(\displaystyle \frac{8\times(2.1)^3}{(2.1)^2}=8\times2.1=16.8\)