Question

‘O’ is the centre of the circumcircle of triangle ABC.

∠A = 40, ∠B = 80, ∠C = 60, BC = 6.4 cm.

(a) What is the diameter of the circle?

(b) What is the length of the other two sides?

| | 40 | 60 | 80 |
| sin | 0.64 | 0.87 | 0.98 |
| cos | 0.77 | 0.50 | 0.17 |
| tan | 0.84 | 1.73 | 5.67 |

Answer 1

(a) Given : In ΔABC

AB = c

BC = a = 6.4 cm

AC = b

∠A = 40°, ∠B = 80°, ∠C = 60°

Let ‘R‘ be the radius of circumcircle of ΔABC