The two triangles at right are similar shapes.
What is the scale factor from shape A to shape B?
Which corresponding sides in A and in B are both known?
What do you need to multiply
by to get ?
Find the missing side lengths.
Identify which sides in A correspond to sides in B.
corresponds to and corresponds to , multiply by the scale factor to find , and divide by the scale factor to find .
If you wanted to make shape A smaller instead of bigger, what is a scale factor you could use?
The scale factor is what you multiply by to increase or decrease the size of a shape.
If a scale factor greater than one created a larger triangle, then a scale factor less than one must create a smaller triangle.
Note that a scale factor cannot be negative because a negative side length is nonexistent.