Which change will double the lateral surface area of a regular triangular pyramid with base length b, height h, and slant height l?

A regular triangular pyramid is a solid figure with r surfaces

- 3 lateral surfaces and one base surface

- the four surfaces are congruent triangles, which is to say that all triangular surfaces have the same base and the same slant heght

- the area of each surface is [1/2] base * slant height.

Then, a change that double the area is any that keep one of the dimensiones and double the other.

So the answer is: double each side, b, of the base triangle while keeping the slant height, l, tha same.

You can also double the slant height, l, while keeping the base triangle, but then the height, h, of the pyramid will increase, by a factor which is not 2.