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

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*3.14* r`

STEP 4: Solve the formula for the unknown

`\begin{gathered} 15.7=2*3.14* r \\ 15.7=6.28r \\ \text{Divide both sides by 6.28} \\ (15.7)/(6.28)=(6.28r)/(6.28) \\ 2.5=r \\ r=2.5\text{ } \end{gathered}`

Hence, the value of the unknown variable r is 2.5