Compute the area A of ∆ABC.
• Take AB to be the base and CX (which is an altitude of ∆ABC) to be the height. Then the area is
A = 1/2 • AB • CX = 1/2 • 75 • CX
• Now take AC to be the base and BY (also an altitude) to be the height. Then
A = 1/2 • AC • BY = 1/2 • 70 • 60 = 2100
The areas must be equal, so we have
2100 = 1/2 • 75 • CX → CX = 4200/75 = 56
