Ravi
Last Activity: 10 Years ago
If the angle subtend at the centre by the chord is 120, the area of the segment will be area of the sector – area of the triangle subtend at the centre.
Area of sector= pi(r)2. (120/360)
Area of triangle= 1/2r2 SinA. where A is the centre. So, A=120
OR
Area of triangle ABC(where A is the centre, b and C lie on the circle)
So, a perpendicular AD dropped from A on BC will bisect it. So, in rt angled triangle ADC, Sin C= Sin 30= AD/ AC
So, AD= AC sin 30= r/2
And similarily, DC= AC cos 30= r
.
Use the dimensions of the three sides of both the right angled triangles to find the area of triangle ABC.(using Heron’s formula or Area= ½ b*h)