7. Scale Drawings and Models
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With an extended ratio you can express the lengths of the sides with respect to the factor x.
H
An extended ratio compares three or more numbers. In an extended ratio a : b : c, the ratio of the first two numbers is a : b, the ratio of the last two numbers is b : c, and the ratio of the first and last numbers is a : c. We want to find the lengths of the sides of a triangle that fit the given extended ratio. 4 : 7 : 10 This means that we can express the lengths of the sides of the triangle as 4x, 7x, and 10x.
| Expression | Substitute | Simplify |
|---|---|---|
| 4x | 4(4) | 16 |
| 7x | 7(4) | 28 |
| 10x | 10(4) | 40 |
Let's add the found lengths to find the perimeter. P = 16 + 28 + 40 ⇒ P = 84 We see that the answer is H.