Exercise 6 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 90 % is 12, which means that we want to find the whole. Let w represent the whole. 12/w=90/100 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.

12/w=90/100

CrossMult

Cross multiply

12* 100= w * 90

Multiply

Multiply

1200=90w

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

1200=90w

DivEqn

.LHS /90.=.RHS /90.

1200/90=90w/90

CancelCommonFac

Cancel out common factors

1200/90=90w/90

SimpQuot

Simplify quotient

1200/90 = w

CalcQuot

Calculate quotient

13.33333... = w

RoundDec

Round to 1 decimal place(s)

13.3 ≈ w

RearrangeEqn

Rearrange equation

w ≈ 13.3

We got that w≈ 13.3 is a solution to the proportion. This means that 12 is 90 % of about 13.3.