• Imagine we are using these two points to draw a triangle where new point E is a right angle with coordinates (-1, -9) • FE = 5 • EC = 4 • FE^2 + EC^2 = FC^2 • (25) + (16) = 41 = FC^2 • FC = square root(41)
Since the TOTAL area is 30 square inches, what you would do is divide 30/3, since you already know how wide it is. And the answer is 10. The envelope is 10 inches tall.
