Sector area Two radii separate the area of a circle into two sectors - the major sector and the minor sector. To calculate the sector area, first find what fraction of the whole circle we have.

Where Pi (π) is of course the number and r is the radius of the circle. Where does this formula come from? One method of obtaining this equation is to integrate dxdy over the area of a circle.

Why is the area of a circle proportional to the square of its radius? And why is that ratio the same as the ratio of the circumference to the diameter?

Two radii close radiusThe distance from the centre of a circle to its circumference. The plural of radius is radii. separate the area of a circle into two sectors - the major sector and the minor ...