AO and OC are both radii of the circle. Length AO = Length OC Draw the line OB. It creates two triangles OCB and OAB. These share the length OB.

Area is the amount of space taken up by a surface or a 2-D shape. It is measured in squares with metric units mm², cm², m² and km². Module 1 (M1) - Geometry & measures - Circumference & area of ...