SAT Mathematics Practice Test 5

The volume of right circular cylinder A is given by the expression $\mathit{\pi }{\mathit{r}}^2\mathit{h},$ where r is the radius of its circular base and h is its height. The volume of a cylinder with twice the radius and half the height of cylinder A is given by $\mathit{\pi }{\left(2\mathit{r}\right)}^2\left(\frac{1}{2}\right)\mathit{h},$ which is equivalent to $4\mathit{\pi }{\mathit{r}}^2\left(\frac{1}{2}\right)\mathit{h}=2\mathit{\pi }{\mathit{r}}^2\mathit{h}$.Therefore, the volume is twice the volume of cylinder A, or $2\times 22=44.$
Choice A is incorrect and likely results from not multiplying the radius of cylinder A by 2. Choice B is incorrect and likely results from not squaring the 2 in 2r when applying the volume formula. Choice D is incorrect and likely results from a conceptual error.