Manan observes that the angle of elevation of the top $P$ of the tower $OP$ at a point $A$ on the ground is $\alpha$, he then walks a distance $AB$ towards the foot $O$ of the tower and finds the angle of elevation as $\beta$, he again walks a distance $BC$ in the same direction and observes the angle of elevation now is $\gamma$. He notices that $a + \beta + \gamma = 180^o; \alpha, \beta, \gamma$ are in A.P. and the distance of $C$ from the foot of the tower is half the distance of $B$ from the foot $O$ of the tower. If the height of tower is $h$, the distance of $A$ from the foot $O$ is $\dfrac{5h}{3\sqrt{3}}$.