The video below works through this example of finding missing side lengths of similar triangles.
The steps I used to solve example one are below, in case you'd like to try it before you watch the video. There is more than one way to attack this problem, however, so your method may be different from mine and still be correct.
Step One: Write the similarity statement, making sure corresponding vertices are in the same position.
Step Two: Write proportionality statement for the sides of the triangles.
Step Three: Use WY to find XY
Step Four: Use proportions to find WX
Finds the scale factor given the dimensions of circles.
Source: The Mona Lisa was painted by Leonardo Da Vinci in the early 1500's. This copy of it is in the public domain.
This example from the art world demonstrates how you can show through proportions whether two rectangles are similar.
