An equilateral triangle ABC is inscribed in a circle centered at O, as shown below. OE is a radius such that it is perpendicular to BC and cuts BC at point D. If OD = 5 cm, then the radius of this circle is
10 cm
We know that a side of an equilateral triangle drawn with vertices on a circle bisects the radius perpendicular to it.
So, the side BC of equilateral triangle ABC bisects the radius OE and hence OD = DE.
Given, OD = 5 cm.
Therefore OE = OD + DE = 5 cm + 5 cm = 10 cm
Hence radius of this circle is 10 cm.