Math Antics
Circles, Circumference and Area
Use π with radius and diameter to find both measures.
Watch on YouTubeUse π with the radius and diameter to measure circles.
Read this first — it covers the idea in plain language with a worked example.
A circle has radius 5 cm. Find its circumference and area (use π ≈ 3.14).
Watch out
For area you square the radius (r × r), not double it. Squaring and doubling are very different.
A short video that walks through this topic.
Use π with radius and diameter to find both measures.
Watch on YouTubeTry a worksheet or work through some problems before the quiz.
A couple of questions to make sure this topic stuck. Retake as many times as you want.
Circumference & Area of Circles
A circle has a diameter of 10 m. What is its circumference? (π ≈ 3.14)