From the top of a platform 7 m high, the angle of elevation of a tower was 30 deg. If the platform was positioned 50√3 m away from the tower, how tall was the tower?
In ΔDEF, G and H are points on side DE and DF respectively. GH is parallel to EF. If G divides DE in the ratio 3:2 and HF is 8 cm, then the length of DF is