Question

What is the formula for finding the area of a sector of a circle with the radius r?

Answer 1

But, you have to do something that proofs that formula or just to write the formula?

Answer 2

A=(1/2)r^2\[\theta\]

whr \[\theta\] is in radian

Answer 3

You need to also know the angle of the sector.

Answer 4

this shows you: http://www.mathwords.com/a/area_sector_circle.htm

Answer 5

Thanks:)

Answer 6

The area of a full circle is \(\pi r^2\).

If we divide it into sectors, we would have a fraction of that area with respect to how large the angle is at the vertex of that sector. If we use degrees, there are 360 degrees in a circle. If we use radians, there are \(2\pi\) radians.
Degrees: \(\large \frac{d}{360} \pi r^2 \quad d = \text{degrees}\)
Radians: \(\large \frac{\theta}{2\pi} \pi r^2 = \frac{\theta}{2} r^2 \quad \theta = \text{radians}\)