Question

If the length of a chord of a circle is 16 cm and is at a distance of 15 cm from the centre of the circle, then
the radius of the circle (in cm) is

Answer 1

Answer:

The line from the centre of the circle to one or the other end of the 16cm line is the radius of the circle, which is also the hypoteneuse of the triangle you have just created. Now using Pythagoras Theorem 15^2 + 8^2 = r^2. So 225+64 = r^2 = 289 therefore r = sqrt 289 = 17cm.