CPM Homework Banner

The two triangles at right are similar shapes.  

  1. 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 ?

  2. Find the missing side lengths.

    Identify which sides in A correspond to sides in B.

    Since  corresponds to and corresponds to , multiply by the scale factor to find , and divide by the scale factor to find .

  3. 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.

A triangle labeled A, with sides labeled in order from shortest to longest: 8, s, and 16.

A triangle labeled B, with sides labeled, in order from shortest to longest: 20, 35, and t.