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Example 5.62 from Prealgebra, 5.6 Ratios and Rate
The Americans with Disabilities Act (ADA) Guidelines for wheel chair ramps require a maximum vertical rise of inch for every foot of horizontal run. What is the ratio of the rise to the run?
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
In a ratio, the measurements must be in the same units. We can change feet to inches, or inches to feet. It is usually easier to convert to the smaller unit, since this avoids introducing more fractions into the problem.
Write the words that express the ratio.
| Ratio of the rise to the run | |
| Write the ratio as a fraction. | |
| Substitute in the given values. | |
| Convert 1 foot to inches. | |
| Simplify, dividing out common factors and units. |
So the ratio of rise to run is to This means that the ramp should rise inch for every inches of horizontal run to comply with the guidelines.
The book's Try It right after this example: same idea, new numbers. Only the answer is given.
Find the ratio of the first length to the second length: inches to foot.
How did it go?