Exercise 3 Page 125

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 the number of which 12 % is 9, which means that we want to find the whole. Let w represent the whole. 9/w=12/100 Now we can solve the proportion we got for w. Let's do this by using the fact that the cross products of any proportion are equal.

9/w=12/100

CrossMult

Cross multiply

9* 100= w * 12

Multiply

Multiply

900=12w

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

900=12w

DivEqn

.LHS /12.=.RHS /12.

900/12=12w/12

CancelCommonFac

Cancel out common factors

900/12=12w/12

SimpQuot

Simplify quotient

900/12 = w

CalcQuot

Calculate quotient

75 = w

RearrangeEqn

Rearrange equation

w = 75

We got that w= 75 is a solution to the proportion. This means that 9 is 12 % of 75.