Thread: sector area

Chord length c in circle radius r.
What is area of the sector created, in terms of c and r?

Originally Posted by Wilmer

Chord length c in circle radius r.
What is area of the sector created, in terms of c and r?

Hi Wilmer,

You can use the Cosine Rule.

The sector angle C is derived from $\displaystyle c^2=R^2+R^2-2RRCosC$

$\displaystyle C=Cos^{-1}\left(\frac{2R^2-c^2}{2R^2}\right)$

Then use this C for the sector area.

This is a well done page.

Thanks (I knew that), BUT without using trig.
In terms of r and c ONLY.