From a point on the ground 12 m from a house, the angle of elevation of the top and bottom of a TV antenna was found to be 51 degree and 42 degree respectively. How tall is the antenna?
tan(51°) = (h + a)/12 (1) where h is height of house and a is length of antenna
tan(42°) = h/12 (2)
Subtract (2) from (1): tan(51°) - tan(42°) = a/12
a = 12*(tan(51°) - tan(42°))
I'll leave you to crunch the numbers.
