Geometry Ratios and Proportions

RATIO AND PROPORTION

By Hanna Javier

Let's take a review

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Multiple Choice

A parallelogram whose sides are

congruent.

• rhombus

• rectangle

• square

• trapezoid

Multiple Choice

A parallelogram whose sides are

congruent and with four right angles.

• rectangle

• rhombus

• square

• kite

Multiple Choice

A quadrilateral whose opposite

sides are parallel

• square

• trapezoid

• parallelogram

• rhombus

A ratio is a comparison between two numbers or quantities.

​RATIO

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​Example:

​There are 3 triangles and 2 squares

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We can write the ratio as: ​

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3:2 or 3 to 2 or ​ 3/2

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A proportion is an equation that shows two ratios are equivalent.

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PROPORTION​

In the given proportion

2:3 = 4:6

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​3 and 4 are called the means, and 2 and 6 are called

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In the given proportion

5:15 = 1:3

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​15 and 1 are called the means, and 5 and 3 are called extremes.

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Multiple Choice

Identify the means $$\frac{4}{5}=\frac{12}{15}$$  

• 4 and 15

• 5 and 12

• 5 and 4

• 15 and 12

Multiple Choice

Identify the extremes $$\frac{4}{5}=\frac{12}{15}$$  

• 12 and 15

• 5 and 12

• 4 and 15

• 4 and 5

Multiple Choice

identify the means in $$6:9=4:6$$  

• 9 and 6

• 9 and 4

• 6 and 6

• 6 and 4

Multiple Choice

identify the extremes in $$\frac{y}{10-y}=\frac{3}{y}$$  

• y and 10-y

• y and 3

• 10-y and 3

• y and y

There are 340 students at Pasay Academy. If the student-to-teacher ratio is 17:2, how many teachers are there?

EXAMPLES

Set up a proportional relationship between the student-to-teacher ratio, by using x to represent the number of teachers.

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students:teacher=students:teachers

​ or

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Solutions

Indira’s photos come in two sizes: 13 cm x 9 cm and 15 cm x 10 cm. Are these dimensions proportional?

EXAMPLES

Solutions

The ratio of fiction books to non-fiction books in Roxane's library is 7 to 4. If Roxane

owns 182 fiction books, how many non-fiction books does she own?

EXAMPLES

Solutions

Multiple Choice

Find the unknown value in the proportion: 2 : x = 3 : 9.

• x = 3

• x = 6

• x = 9

• x = 12

Multiple Choice

he ratio of number of boys to girls in a classroom is 6 to 5. If there are a total of 48 boys in the classroom, find the number of girls in the classroom. Which of the following best describes the problem?

• 6:5 = 48:x

• 5:6 = 48:x

• 6:5 = x:48

• none of the choices

Multiple Choice

Which of the following is proportional to 3 : 2?

• 9 : 8

• 6 : 4

• 12 : 10

• 12 : 9

Thank you for listening

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