Chapter 6, Problem 9MCQ

To determine

To solve: the proportion $\frac{.4}{c}=\frac{1.2}{21}$ and find the value of $c$ .

Answer to Problem 9MCQ

The value of $c$ in proportion $\frac{.4}{c}=\frac{1.2}{21}$ is $7$ .

Explanation of Solution

Given information : consider, the proportionprovided in the question,

  $\frac{.4}{c}=\frac{1.2}{21}$ .

Formula used: cross product property −

  $\begin{array}{l}\frac{a}{b}=\frac{c}{d}\\ ab=cb\\ \end{array}$

Calculation : to solve the proportion use cross products propertythen multiply and divide the result by 1.2 .

  $\begin{array}{l}\frac{.4}{c}=\frac{1.2}{21}\\ .4·21=1.2·c\\ 8.4=1.2·c\\ c=7\end{array}$

Hence,

Thus,The value of $c$ in proportion $\frac{.4}{c}=\frac{1.2}{21}$ is $7$ .