Chapter 6.3, Problem 21E

To determine

To evaluate: the proportion $\frac{3}{21}=\frac{c}{35}$ .

Answer to Problem 21E

The answer of the proportion $\frac{3}{21}=\frac{c}{35}$ is $c=5$ .

Explanation of Solution

Given information: The provided proportion is $\frac{3}{21}=\frac{c}{35}$ .

Calculation :

The method used here to solve the proportion is cross products property. The product of the numerator of one ratio and of the denominator of the other is known as a cross product.

  $\begin{array}{l}\frac{3}{21}=\frac{c}{35}\text{ [Write the proportion}\text{.]}\\ 3\times 35=21\times c\text{}\text{}\text{ [Apply cross products property}\text{.]}\\ 105=21c\text{ [Multiply}\text{.]}\\ \frac{105}{21}=\frac{21c}{21}\text{ [Divide each side by 21to place the variable on one side of the equation}.]\\ c=5\text{ [Simplify}\text{.]}\end{array}$

Hence, the solution of the proportion $\frac{3}{21}=\frac{c}{35}$ is $c=5$ .