# You can unwrap a circle into strips to form a triangle In most schools you would be told outright that the area of a circle is  π r². The formula is easy enough, but you can also come up with it yourself by unwrapping the circle into infinite number of strips and form a triangle to measure its area, like below. Animated: ![[Unwrap circle into strips.gif]] In pictures: ![[Dissecting a circle.png]] ![[Unrolling the rings.png]] --- Source: [BetterExplained](https://betterexplained.com/calculus/lesson-1/)