Answer: 76.46 m
Explanation:
Height of tower = 75m
Support wire 20 m from top
Angle formed (α) = 46°
Using Pythagoras :
Sinα = opposite / hypotenus
Height used = height of tower - 20 m from top
Height = opposite = (75 - 20)m = 55m
Hypotenus = Length of support wire
Sin 46 = 55m / hypotenus
Hypotenus * sin 46 = 55
0.71934 * hypotenus = 55
Hypotenus = 55/0.71934
Hypotenus = 76.458976
Hence, Lenght of support wire = 76.46 m