HomePricing

Area of circle sector from angle

Area of a sector of a circle from angle

The math skill being taught is calculating the area of a sector of a circle when given the sector angle. This involves determining the fraction of the circle represented by the sector and using it to find the proportional area of the entire circle.

Learn area of circle sector from angle

Teaching Transcript

🎙️

What is the area of the sector of this circle with sector angle of 120 degrees?

A full circle is 360 degrees, so our sector covers one third of the circle.

The circle has a radius of 9, so we can calculate the area of the full circle with pi times the radius squared, That would be a full area of 81 pi

But we only have one third of the circle, so we need to multiply by one third

So our sector area is 27 pi.

If we want to have it as a decimal, we can use 3.14 for pi, and it would be approximately 84.8