Answer:
F. 82
Step-by-step explanation:
To calculate the length of BC, Pythagoras theorem will be used.
It says, Hypotenuse^2 = Perpendicular^2 + Base^2
In our case, Perpendicular = AB = 18 and Base = AC = 80
therefore,
Hypotenuse^2 = 18^2 + 80^2 = 6724
Hypotenuse = BC = = 82