JAMB - Mathematics (1997 - No. 23)
Each of the base angles of a isosceles triangle is 58° and the verticles of the triangle lie on a circle. Determine the angle which the base of the triangle subtends at the centre of the circle.
128o
16o
64o
58o
Spiegazione
Base angle of the triangle = 58°.
The third angle = 180° - (58° + 58°)
= 64°
Angle subtended at the centre = \(2 \times 64° = 128°\) (angle at the centre is twice the angle at the circumference).