(2005? The AD height of Shenzhen Building is 10 meter, and there is a tower BC not far away. Someone measured the elevation angle of the bottom B at 60 and climbed to the top of the building at D.

Solution: BE⊥AD when passing through point B, and extend the line of AD at point E (1 point).

In Rt△ bed, the elevation angle of point B at the top of the tower measured at point \d is 30,

∴∠BDE=60 degree.

Let DE=x, then BE = 3x. (2 points)

In Rt△BEA, ∠BAE=30 degrees, BE = 3x.

∴ AE = 3x。 (3 points)

∴AD=AE-DE=3x-x=2x= 10.

∴ x = 5。 (4 points)

∴ BC = AD+DE =10+5 =15 (m). (5 points)

Answer: The height of BC Tower is15m.