Exercise 1 Page 141

In the percent proportion, the ratio of the part a to the whole b is equal to the percent p written as a fraction. a/b=p/100 Given any two of these three variables, we can find the third one. In this exercise, we are given the values a= 21 and b= 70, and we are looking for the percent p.

a/b=p/100

SubstituteII

a= 21, b= 70

21/70=p/100

ReduceFrac

a/b=.a /7./.b /7.

3/10=p/100

MultEqn

LHS * 100=RHS* 100

300/10=p

CalcQuot

Calculate quotient

30=p

RearrangeEqn

Rearrange equation

p=30

This means that 21 is 30 % of 70.