Question

Substitute the given values into the given formula and solve for the unknown variable. If necessary, round to one decimal place. (Use the approximation 3.14 for π.) C=2πr; C=15.7 (Circumference of a circle)C=2πr; C=15.7 (Circumference of a circle)

Answer 1

SOLUTION

Given the question in the question tab, the following are the solution steps to answer the question.

STEP 1: Write the given formula

$C=2\pi r$

STEP 2: Write the given values

$C=15.7,\pi=3.14,r=\text{?}$

STEP 3: Substitute the values into the formula

$15.7=2\times3.14\times r$

STEP 4: Solve the formula for the unknown

$\begin{gathered} 15.7=2\times3.14\times r \\ 15.7=6.28r \\ \text{Divide both sides by 6.28} \\ \frac{15.7}{6.28}=\frac{6.28r}{6.28} \\ 2.5=r \\ r=2.5\text{ } \end{gathered}$

Hence, the value of the unknown variable r is 2.5