Question

"The difference between the circumference and diameter of a wheel is 18cm. Find the radius of the wheel. Use 3.14 for Pi. Round to the nearest tenth."

Answer 1

Answer:

$4.2\ \text{cm}$

Step-by-step explanation:

d = Diameter of wheel

The difference between the circumference and diameter of a wheel is 18 cm.

$2\pi r-d=18\\\Rightarrow \pi d-d=18\\\Rightarrow d(\pi-1)=18\\\Rightarrow d=\dfrac{18}{\pi -1}\\\Rightarrow d=\dfrac{18}{3.14-1}\\\Rightarrow d=8.41\ \text{cm}$

The diameter of the wheel is 8.41 cm so the radius will be $\dfrac{8.41}{2}=4.205\approx 4.2\ \text{cm}$.