Radius of a circle is 10 cm. Angle made by chord AB at the centre of this circle is 60 degree. What is the length of this chord?

10 cm

OA = OB = 10 cm

\(\Delta \)OAB is an isosceles triangle.

So, \(\angle\)OAB = \(\angle\)OBA = \(\frac{180\;-\;60}{2}\) = \({60}^\circ\)

Since \(\angle\)OAB = \(\angle\)OBA = \(\angle\)AOB = \({60}^\circ\), \(\Delta \)OAB is an equilateral triangle.

So, OA = OB = AB = 10 cm.

Therefore, the length of the chord is 10 cm.