Calculate height of building a rock is thrown from

A rock is thrown from a building with an initial velocity of 8.46 m/s at an angle of 52 degrees above the horizontal (aka, top of the building). The rock hits the ground 10.7m away from the bottom of the building. How tall is the building?

Acceleration is -9.8 m/s. Help?

By R = (Ux) x t
=>10.7 = ucos52* x t
=>t = 10.7/[8.46 x cos52*]
=>t = 2.05 sec
=>By s = ut + 1/2gt^2
=>h = -usin52* x 2.05 + 1/2 x 9.8 x (2.05)^2
=>h = -8.46 x sin52* x 2.05 + 1/2 x 9.8 x (2.05)^2
=>h = 6.90 m