Question

If the diameter of a circle is changed from 5 cm to 10 cm, how will the circumference change?

Answer 1

Step 1

Write out an expression for the circumference of a circle

`\begin{gathered} C\text{ =}\pi d \\ C\text{ is the circumference} \\ d\text{ is the diameter} \end{gathered}`
`\begin{gathered} \text{when d = 5}cm \\ C=5\pi cm \end{gathered}`
`\begin{gathered} \text{when d=10cm} \\ C=10\pi cm \end{gathered}`

Thus, when the diameter changed from 5cm to 10cm, the circumference is twice the previous size

That is, the circumference when the diameter is 10cm is 2 times the circumference when the diameter is 5cm