# Similar Triangles -What are they?

## Similar Triangles - What are they? - How it Works - Video

Definition:

### Why are they similar?

Why are they similar?:

### Example 1

Example 1:

Similar means that the ratio of the corresponding sides are congruent and the corresponding angles are the same. In this case, we are dealing with the sides since all of them are right triangle.

For triangle A we chose the ratio smaller side over longer side ==> 6 cm over 18 cm. That reduces to 1/3.

Let's go ahead and find the ratios of the other triangles. Remember we have to keep the same ratio that we did for triangle A.

Triangle B is 5 cm over 15 cm ==> 1/3. The units cancel after being reduced.

Triangle C is 10 cm over 40 cm ==> 1/4. The units cancel after being reduced.

Triangle D is 8 cm over 24 cm ==> 1/3. The units cancel after being reduced.

Triangle E is 3 cm over 9 cm ==> 1/3. The units cancel after being reduced.

The only triangle that is different is triangle C. So our final answer is triangle A is not similar to triangle C.

Example 2:

Example 3:

## Live Worksheet

Here is the link if you prefer.