Similarity Proofs

Front

What is the definition of similar triangles?

Back

Triangles that have the same shape but may differ in size; their corresponding angles are equal and their corresponding sides are in proportion.

Front

What does AA stand for in similarity proofs?

Back

AA stands for Angle-Angle; if two angles of one triangle are equal to two angles of another triangle, the triangles are similar.

Front

What does SSS stand for in similarity proofs?

Back

SSS stands for Side-Side-Side; if the sides of one triangle are in proportion to the sides of another triangle, the triangles are similar.

Front

What does SAS stand for in similarity proofs?

Back

SAS stands for Side-Angle-Side; 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

What does ASA stand for in similarity proofs?

Back

ASA stands for Angle-Side-Angle; if two angles and the included side of one triangle are equal to two angles and the included side of another triangle, the triangles are similar.

Front

Are triangles with angles 40°, 60°, and 80° similar to triangles with angles 40°, 50°, and 90°?

Back

No, because the angles are not all equal.

Front

If CB / DM = AC / ?, what is the missing term?

Back

AD.

Front

If two triangles have their angles congruent, what can we conclude?

Back

The triangles are similar.

Front

What is the relationship between the sides of similar triangles?

Back

The lengths of corresponding sides are proportional.

Front

If the ratio of the sides of two similar triangles is 2:3, what is the ratio of their areas?

Back

The ratio of their areas is 4:9 (the square of the side ratio).