Exercise 4 Page 243

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 10% of 40.5 is by thinking about 10 as the percent and 40.5 as the whole. Let's substitute p= 10 and w= 40.5 into the formula and solve for a using the Properties of Equality.

a/w=p/100

SubstituteII

p= 10, w= 40.5

a/40.5=10/100

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Solve for a

MultEqn

LHS * 40.5=RHS* 40.5

a/40.5* 40.5=10/100 * 40.5

FracMultDenomToNumber

a/40.5* 40.5 = a

a=10/100 * 40.5

MoveRightFacToNum

a/c* b = a* b/c

a=10* 40.5/100

Multiply

Multiply

a=405/100

CalcQuot

Calculate quotient

a= 4.05

Knowing the value of a, let's look at the completed percent proportion. 4.05/40.5=10/100 We found that 4.05 is 10 % of 40.5.

Checking Our Answer

Checking Our Answer

We can use a model to check our answer.