you can use similar triangle to make known degrees in problems to make then easier to solve. With similar triangle, the angles are the same, but the scale is different. So by using this, one can solve both at the same time, and just just scale up the smaller one or scale down the larger, by the given/found scale.
You can indirectly determine the measure or size of something that is tedious to measure by hand.
Or by knowing that the triangles are similar, you can find the corresponding sides, angles or even other variables based on the information that is given.
If a triangle is similar to another, they are proportional; usually have congruent angles, which means that the only differing variable is the scale factor, or relative position.
