Sides of a triangle are 9 cm, 6 cm and 5 cm. What is the value of circumradius of this triangle ?
Answer & explanation
Correct answer: option 3
Let be assume a, b and c is the sides of the triangle.
= Area of triangle = \(\sqrt {s(s\;-\;a)(s\;-\;b)(s\;-\;c) }\)
= s = \(\frac{a\;+\;b\;+\;c}{2}\) = \(\frac{20}{2}\) = 10 cm
= \(\sqrt {10(10\;-\;9)(10\;-\;6)(10\;-\;5) }\)
= A = \(\sqrt {200 }\)
= A = 10\(\sqrt {2 }\)
= R = \(\frac{abc}{4A}\)
= R = \(\frac{9 \;×\; 6\;×\;5 }{4\;×\;10√2}\)
= R = \(\frac{270}{40√2}\)
= R = \(\frac{27√2}{8}\) cm
Therefore, R is \(\frac{27√2}{8}\) cm.