Exercise 4 Page 185

There are many different ways to compare amounts or quantities. A ratio is a comparison of two quantities by division. For example, the ratio of a to b can be written in two different ways. a/b or a: b We want to find the value of the ratio of jojoba oil to essential oils. We can write the fraction that represents this ratio. We will write the number of tablespoons of jojoba oil in the numerator and the number of teaspoons of essential oils in the denominator. l jojoba oil→ essential oils→ 12/12 Recall that fractions can be thought of as dividing the numerator by the denominator. 12/12=12÷ 1/2 Before we evaluate this expression, let's first rewrite the expression so that all of the numbers are fractions.

12÷ 1/2

NumToDivByOne

a=a/1

12/1÷ 1/2

Dividing two fractions is the same as multiplying the first fraction by the reciprocal of the second fraction. 12/1÷ 1/2=12/1* 2/1 When we multiply fractions, we need to remember that the product of two fractions is equal to the product of the numerators divided by the product of the denominators. Let's find the given product!

12/1* 2/1

MultFrac

Multiply fractions

12* 2/1* 1

Multiply

Multiply

24/1

DivByOne

a/1=a

24

The ratio is 24, 24 to 1, or 24:1. This means that the number of teaspoons of jojoba oil is 24 times the number of teaspoons of essential oils.