How can you solve real world problems using the triangle proportionality theorems?

Question

How can you solve real world problems using the triangle proportionality theorems?

Answer 1

You can determine values that you can't directly measure.

 

E.g., on a sunny day you can measure the length of your shadow and a tree's shadow.

 

You can also measure your height; but you can't directly measure the tree's height (easily).

 

Using similar triangles whose sides are proportional you can calculate the height of the tree.