CHAPTER 7: SIMILARITY 7.1 Ratio and Proportion

A RATIO is… A comparison of a number “a” and a nonzero number “b” using division Ratios can be written 3 ways: 1) As a FRACTION (or an equivalent decimal) 2) Using WORDS 3) Using a COLON

Example 1 Simplify the ratio. a) 60cm : 200cm b)

Example 2 Use ratios In the diagram, AB:BC is 4:1 and AC=30. Find AB and BC.

Example 3 Use ratios The perimeter of a rectangle is 80 feet. The ratio of the length to the width is 7:3. Find the length and the width of the rectangle.

You Try It.. 1) In the diagram, EF:FG is 2:1 and EG=24. Find EF and FG. 2) The perimeter of a rectangle is 84 feet. The ratio of the length to the width is 4:3. Find the length and the width of the rectangle.

Solving a Proportion Proportion: an equation that states that two ratios are equal You can solve using the Cross Product Property Ex)

Example 4 Solve the proportion

You Try It… Solve the following Proportions: a)b)c)

Example 5 Turn to p. 360 in your textbook.

You Try It… a) Use the map of Texas and a ruler to estimate the distance between the two cities.

Homework