Exercise 21 Page 127

Let's start by recalling that the percent proportion is a proportion that sets the ratio of a part of a whole equal to the ratio of a percent out of 100. part/whole=percent/100 We want to find what percent of 60 is 12. Let n represent the percent. 12/60=n/100 Now we can solve the proportion we got for n. Let's do this by using the fact that the cross products of any proportion are equal.

12/60=n/100

CrossMult

Cross multiply

12* 100= 60 * n

Multiply

Multiply

1200=60n

Finally, we will use the Division Property of Equality to get the value of n.

1200=60n

DivEqn

.LHS /60.=.RHS /60.

1200/60=60n/60

CancelCommonFac

Cancel out common factors

1200/60=60n/60

SimpQuot

Simplify quotient

1200/60 = n

CalcQuot

Calculate quotient

20 = n

RearrangeEqn

Rearrange equation

n = 20

We got that n= 20 is a solution to the proportion. This means that 12 is 20 % of 60.