Scaling factor of the base and any cross section area in tetrahedron.

Question

I'm given that the scaling factor of the areas between base and any cross section parallel to the base in a tetrahedron is $(\frac{H-h}{H})^2$, where $H$ is the height of the tetrahedron and $h$ is the height from base to the cross section.

I don't understand this, could someone help me to visualize this?

Thank you.

Answer 1

Here is a drawing:

Is this helping?