In triangle OCB,
cos θ | = | |
θ | = | Cos–1 ----- (i) |
And BC2 | = | OB2 – OC2 |
= | r2 – (r – h)2 | |
= | 2rh – h2 | |
AB | = | 2BC = 2 |
Area of triangle OAB | = | × AB × OC |
= | (2)(r – h) | |
= | (r – h) ---- (ii) | |
Area of ACBD segment | = | Area of arc OAB – area of ΔOAB |
From (i) and (ii), | ||
= | r2(2θ) – (r – h) | |
= | r2 Cos–1 – (r – h) |