Similar Triangles

Front

What does it mean for two shapes to be similar?

Back

Two shapes are similar if they have the same shape but not necessarily the same size. Their corresponding angles are equal, and their corresponding sides are in proportion.

Front

Are congruent shapes also similar?

Back

True. Congruent shapes are similar because they have the same shape and size.

Front

What is the scale factor in similar triangles?

Back

The scale factor is the ratio of the lengths of corresponding sides of two similar triangles.

Front

If triangle ABC is similar to triangle DEF, what can we say about their angles?

Back

The corresponding angles of triangle ABC and triangle DEF are equal.

Front

What is the AA criterion for similarity?

Back

The AA (Angle-Angle) criterion states that if two angles of one triangle are equal to two angles of another triangle, the triangles are similar.

Front

What is the SSS criterion for similarity?

Back

The SSS (Side-Side-Side) criterion states that if the sides of one triangle are in proportion to the sides of another triangle, the triangles are similar.

Front

What is the SAS criterion for similarity?

Back

The SAS (Side-Angle-Side) criterion states that if two sides of one triangle are in proportion to two sides of another triangle and the included angles are equal, the triangles are similar.

Front

If the sides of triangle ABC are 3, 4, and 5, and the sides of triangle DEF are 6, 8, and 10, are the triangles similar?

Back

Yes, triangle ABC and triangle DEF are similar because their corresponding sides are in proportion (3:6, 4:8, 5:10).

Front

How do you find the missing side in similar triangles?

Back

You can use the proportion of the corresponding sides to find the missing side. Set up a proportion and solve for the unknown.

Front

If triangle ABC is similar to triangle DEF and AB = 5, DE = 10, what is the scale factor?

Back

The scale factor is 2, since DE/AB = 10/5 = 2.