Tutor: Circles
Stuck on a circle problem? Review the essentials below, then send a demo request describing where you got stuck.
1 Quick recap before you ask
Most circle questions are answered by these four lines. Check which one your problem needs.
CircumferenceC = 2πr or C = πd. Distance around the circle.
AreaA = πr². Space inside the circle. Square the radius first.
Arc lengtharc = (θ/360) × C. A fraction of the circumference.
Sector areasector = (θ/360) × A. A fraction of the total area.
The diameter trapFormulas need the radius. Given the diameter? Halve it first: r = d ÷ 2.
House rulesπ = 3.14 everywhere, and answers round to 2 decimal places.
2 Ask a tutor
Describe your circle problem and where you got stuck. A tutor will walk you through it.