# Scaling Up Investigation 4.2. Warm Up Solve the following problems. 1. X = 7 16 22 2. There are 450 students and 15 teachers in a school. The school hires.

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Scaling Up Investigation 4.2

Warm Up Solve the following problems. 1. X = 7 16 22 2. There are 450 students and 15 teachers in a school. The school hires two new teachers. How many students should attend the school to keep the student- teacher ratio the same?

Vocabulary Ratio: comparison of two quantities by division Proportional: corresponding lengths have the same ratio Enlarge: make bigger Similar: angles congruent and lengths proportional Scale Factor: ratio of one object to another similar object Dimension: measure of an object

Launch How can I enlarge this picture and keep it proportional?

Exploration

Problem 4.2 Raphael is closing his bookstore. He wants to place a full-page advertisement in the newspaper to announce his going-out- of-business-sale. A full-page ad is 13 by 22, which allows for a white border around the ad. Raphael used his computer to make an 8½ by 11 model of the advertisement, but he wants the newspaper ad department to enlarge it to full-page size. Is this possible? Explain your reasoning.

Follow Up 4.2 What would you suggest Raphael say to the ad department about making a full- page, similar ad from his model? Hint: Give detailed directions

Instructions for exploration Work with your group to answer the problems You may use grid paper if you would like Remember, the ad must remain similar to the original

Summary Have groups give their solutions and explain. QUESTIONS TO ASK How did you get your answer? Why wouldnt the ad take up the entire page? What would happen if you filled the page with the ad? Were the directions you wrote for the ad department specific?

ACE 8 (Refer to 7 for needed information) 9 a & b (Have students measure the drawing first) Finish for homework if necessary

Materials Stretching and Shrinking teacher and student book Grid/graph paper Pencils 1 ruler per group 1 sheet of copy paper 1 full-page newspaper ad Calculator (optional)

Technology LCD projector & computer Calculator

Alternative Assessment Have students design an advertisement and enlarge it to a specified size. They should give detailed explanations of each step.

Writing Have students explain their conclusion in their math journal. Include an explanation of the relationship between similar and scale factor.

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