And also, for the second question, my mind is blown.

Here's all I have.

The two upper triangle's areas add up to equal the triangle on the bottoms' area.

The ratio of the areas between the triangles are : 16/25, 9/16, and 9/25.

Therefore, the ratios of the corresponding sides are their square roots:

4/5, 3/4, and 3/5 are the ratios of proportionality ( I think thats what its called?)

Thanks for answering!