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Ratio ? A comparison of 2 quantities.. Can be written as:a to ba:ba/b. Ex:1 Writing a ratio. The length of a model car is 4in long. The actual length of the car is 15ft long. What is the ratio of the length of the model to the length of the actual car?. 4in. 15ft. =. Must have same units in nu
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1. Chapter 7Similarity Sec. 7 1
Ratios & Proportions
2. Ratio A comparison of 2 quantities. Can be written as:
a to b
a:b
a/b
3. Ex:1 Writing a ratio The length of a model car is 4in long. The actual length of the car is 15ft long. What is the ratio of the length of the model to the length of the actual car?
4. Proportion A statement that sets two ratios equal to each other. Can be reduced to the same fraction.
Write it as:
8. Ex.2: Solve each Proportion
9. Scale Drawings: The scale is usually located at the bottom of the map or in the legend.
The scale is a ratio
You will use it to set up a proportion to solve a problem.
Problem like: How many miles is Denver from Louisville?
It usually looks like:
1in = 50miles
2cm = 80km
10. Example 3: Use proportions to solve the following problem. 2 cities are 3.5in apart on a map. The scale is 1in = 50miles. Find the actual distance.
Step 1: Set up the proportion with the scale as one ratio and the actual distances as the other. Keep like units in proper places.