Ten multiple-choice questions check circumference and area of circles. Several include a diagram. Each question states whether to use \(3.14\) for \(\pi\) or to leave the answer in terms of \(\pi\). Choose the one correct answer, then read the explanation to see which common mistake each wrong choice shows.
What is the radius of the circle?
What is the circumference? Use \(3.14\) for \(\pi\).
What is the area of the circle? Use \(3.14\) for \(\pi\).
A circle has a diameter of \(8\text{ cm}\). What is its area? Use \(3.14\) for \(\pi\).
The circumference of a circle is \(31.4\text{ cm}\). What is its diameter? Use \(3.14\) for \(\pi\).
A circle has radius \(7\text{ cm}\). What is its area in terms of \(\pi\)?
What is the area of the semicircle? Use \(3.14\) for \(\pi\).
What is the area of the quarter circle? Use \(3.14\) for \(\pi\).
The radius of a circle is doubled. What happens to its area?
A wheel has a diameter of \(2\text{ ft}\). How far does it roll in \(50\) turns? Use \(3.14\) for \(\pi\).
🎉 Quiz complete!
Remember:
- Diameter is twice the radius: \(d=2r\).
- Circumference: \(C=\pi d=2\pi r\), measured in linear units.
- Area: \(A=\pi r^{2}\), measured in square units.
- \(\pi\) is about \(3.14\); leave answers in terms of \(\pi\) when asked.
- A semicircle is half a circle; its perimeter includes the diameter.
See every chapter on the Grade 7 math page.