By how much is the volume of a square-based pyramid increased when all the dimensions are doubled?

100%

400%

800%

200%

When all dimensions of a square-based pyramid are doubled, the volume of the pyramid is increased by a factor of 8, which is equal to 800%.

To see why, we can consider the volume of a pyramid, which is given by the formula V = (1/3) * base area * height.

If we double all the dimensions, the base area will increase by a factor of 4 (since the base is a square and both sides are doubled), and the height will also double.

So the new volume will be V' = (1/3) * (4 * base area) * (2 * height) = (4/3) * base area * height.

The new volume (V') is 4/3 times the original volume (V).

Therefore, the volume is increased by a factor of 4/3, which is equal to 1.333... or 133.33...%.

In terms of percentage, it can be approximated to 133.33...% or 200%.

So the correct answer is 200%.