Exercise 5 Page 249

The percent equation is an equation in which the part is equal to the product of the corresponding percent and the whole. We can represent a is p percent of wwith the following equation. a= p% * wWe can find what number's 80% is equal to 8 by substituting p%= 0.8 and a= 8 into the formula and solve for w using the Properties of Equality.

a= p% * w

SubstituteII

p%= 0.8, a= 8

8= 0.8 * w

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Solve for w

DivEqn

.LHS /0.8.=.RHS /0.8.

8/0.8=0.8* w/0.8

CancelCommonFac

Cancel out common factors

8/0.8=0.8* w/0.8

SimpQuot

Simplify quotient

8/0.8=w

CalcQuot

Calculate quotient

10=w

RearrangeEqn

Rearrange equation

w= 10

Knowing the value of w, let's look at the completed percent equation. 8= 80% * 10 We found that 8 is 80 % of 10.

Checking Our Answer

Checking Our Answer

We can use a model to check our answer.