Calculate the angle at the center of a circle.subtended by a chord 6cm from the centre of the circle radius 10cm
make a sketch.
let that central angle be θ
we can use the cosine law:
6^2 = 10^2 + 10^2 - 2(10)(10)cosθ
200cosθ = 164
cosθ = 41/50
θ = appr 34.9°
or
In your sketch of the triangle, drop a perpendicular
call the central angle of the triangle k, (2k will be your central angle you want)
the perpendicular will hit the midpoint of the chord, so
sink = 3/10
k = appr 17.458
2k = 2(17.458) = 34.9° , as before