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Section 8.1 Ratio and Proportion. OBJECTIVE: To write ratios and solve proportions BIG IDEA: Proportionality ESSENTIAL UNDERSTANDINGS: A ratio can be written to compare two quantities An equation can be written stating that two ratios are equal
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Section 8.1Ratio and Proportion OBJECTIVE: To write ratios and solve proportions BIG IDEA: Proportionality ESSENTIAL UNDERSTANDINGS: A ratio can be written to compare two quantities An equation can be written stating that two ratios are equal If the equation contains a variable, it can be solved to find the value of the variable MATHEMATICAL PRACTICE: Attend to precision
Ratio of a to b: a ____________________ of two quantities by division. You can write the ratio of two numbers a and b, where , in three ways: • You usually express a and b in the same unit and write the ratio in simplest form. Students need to be comfortable with ratios written as fractions, as well as decimals and percents. Ratio
A) • B) • C) • D) EX 1: Simplify the ratios
A) length of a tennis racket: 2 feet 4 inches length of a table tennis paddle: 10 inches • B) diameter of table tennis ball: 40 mm diameter of tennis ball: 6.8 cm EX 2: Write the ratio of the first measurement to the second measurement
3. Triangle XYZ has an area of . The ratio of the base of to the height of the triangle is 2:1. Find the base and height of the triangle. Using Ratios
4. The measures of the angles in a triangle are in an extended ratio 3:4:8. Find the measures of the angles. Using Ratios
Proportion: an ____________________ that states that _______________ ratios are equal. • The first and last numbers in a proportion are the ____________________. The middle two numbers are the ____________________. Proportion
Cross Product Property: the product of the ____________________ equals the product of the ____________________ • 1) Reciprocals • 2) Switch the means • 3) Add the denominator to the numerator Properties of Proportions
A) • B) • C) • D) EX 5: Solve the proportion
A photo of a building has the following measurements: width of and height of 2.75 in • a) The actual building is wide. How tall is the actual building? • b) The door height in the photo is 0.5 inches. What is the height of the door in the actual building? EX 6: Solve for the dimensions of the building
8.1 p. 46118, 19, 20, 22, 26 – 46 evens, 47, 56, 58, 62, 65, 66, 21 questions