9-1 and 9-2: Dilations and Ratios Review

Front

What is a dilation in geometry?

Back

A dilation is a transformation that produces a figure similar to the original by increasing or decreasing its size, while maintaining the same shape.

Front

What is the scale factor in a dilation?

Back

The scale factor is the ratio of the length of a side of the image to the length of the corresponding side of the original figure.

Front

What does it mean for figures to be congruent?

Back

Congruent figures are figures that have the same shape and size.

Front

How do you solve a proportion?

Back

To solve a proportion, you can cross-multiply and then divide to find the unknown value.

Front

What is the extended ratio?

Back

An extended ratio compares three or more quantities, showing their relative sizes.

Front

If a triangle has angles in the ratio of 2:4:9, how do you find the measures of the angles?

Back

To find the measures, first add the parts of the ratio (2+4+9=15), then divide 180° by 15 to find the value of one part, and multiply each part by that value.

Front

What is the relationship between the coordinates of a point before and after dilation?

Back

The coordinates of a point after dilation can be found by multiplying the original coordinates by the scale factor.

Front

What is the relationship of oranges to fruit if there are 2 oranges in a total of 6 fruits?

Back

The relationship can be expressed as a ratio of 2:6, which can be simplified to 1:3.

Front

What is the difference between similar and congruent figures?

Back

Similar figures have the same shape but not necessarily the same size, while congruent figures have both the same shape and size.

Front

How do you determine if two ratios are equivalent?

Back

Two ratios are equivalent if their cross products are equal.