Similarity

Front

What does it mean for two figures to be congruent?

Back

Two figures are congruent if they are the same size and shape.

Front

What does it mean for two figures to be similar?

Back

Two figures are similar if they have the same shape but not necessarily the same size.

Front

What is a scale factor?

Back

A scale factor is a number that scales, or multiplies, some quantity. In similar figures, it is the ratio of the lengths of corresponding sides.

Front

If two triangles have sides in the ratio 2:3, are they similar?

Back

Yes, if their corresponding angles are also congruent.

Front

What is the relationship between corresponding angles in similar figures?

Back

Corresponding angles in similar figures are always congruent.

Front

If triangle ABC is similar to triangle DEF, and the length of side AB is 4 cm and side DE is 8 cm, what is the scale factor?

Back

The scale factor is 2.

Front

If two figures are similar, what can be said about their perimeters?

Back

The ratio of their perimeters is equal to the scale factor.

Front

How can you determine if two polygons are similar?

Back

Two polygons are similar if their corresponding angles are equal and the lengths of their corresponding sides are proportional.

Front

What is the formula for finding the area of similar figures?

Back

The area ratio of similar figures is the square of the scale factor.

Front

If the scale factor of two similar rectangles is 1:4, what is the ratio of their areas?

Back

The ratio of their areas is 1:16.