Exercise 17 Page 245

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. We can represent a is p percent of wwith the given proportion. part/whole=percent/100 ⇔ a/w=p/100We can find what number's 25% is 9 by thinking about 25 as the percent and 9 as a part of the whole. Let's substitute a= 9 and p= 25 into the formula and solve for w using the Properties of Equality.

a/w=p/100

SubstituteII

a= 9, p= 25

9/w=25/100

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Solve for p

MultEqn

LHS * w=RHS* w

9/w* w=25/100 * w

FracMultDenomToNumber

a/w* w = a

9=25/100 * w

MoveRightFacToNum

a/c* b = a* b/c

9=25w/100

MultEqn

LHS * 100=RHS* 100

9* 100=25w/100* 100

FracMultDenomToNumber

a/100* 100 = a

9* 100=25w

Multiply

Multiply

900=25w

DivEqn

.LHS /25.=.RHS /25.

900/25=w

CalcQuot

Calculate quotient

36=w

RearrangeEqn

Rearrange equation

w= 36

Knowing the value of w, let's look at the completed percent proportion. 9/36=25/100 We found that 9 is 25 % of 36.

Checking Our Answer

Checking Our Answer

We can use a model to check our answer.