McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
7. Scale Drawings and Models
Continue to next subchapter

Exercise 28 Page 605

With an extended ratio you can express the lengths of the sides with respect to the factor x.

H

Practice makes perfect

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.

We know that the longest side of the triangle is 40 cm. 10x=40 Let's solve this equation and find x.
10x= 40
x=4
Now, to find the perimeter of the triangle let's find the length of each side of the triangle separately and then add them up.
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.