Sector is a part of a circle bounded by two radii and the arc between them.
Arc is a part of the circumference that corresponds to a central angle.
Arc length
$$l=\frac{\alpha}{360^\circ}\times 2 \times \pi \times r=r\times\theta$$
where,
l— arc length;
α— central angle in degrees;
θ— central angle in radians;
r— circle radius.
Sector area
$$S=\frac{\alpha}{360^\circ}\times \pi \times r^{2}=\frac{1}{2}\times r^{2}\times\theta$$
where,
S— sector area;
α— central angle in degrees;
θ— central angle in radians;
r— circle radius.
See also:
Sector and Arc FAQ
What is the difference between a sector and an arc?
An arc is part of a circle's circumference, while a sector is the region enclosed by two radii and the arc between them.
How do you find arc length and sector area?
Arc length is found from the radius and central angle, and sector area is the same fraction of the full circle's area as the central angle is of 360 degrees.
