I mean it would be A and D because I don't know why they are both the same answer. If 10 books were sold yesterday, at LEAST 20 are needed to make the goal.
The three missing lengths are the left hypotenuse, x, the middle altitude, y, and the right hypotenuse, z.
9/y = y/16
y^2 = 9 * 16
y^2 = 144
y = 12
9^2 + 12^2 = x^2
x^2 = 225
x = 15
12^2 + 16^2 = z^2
z^2 = 400
z = 20
From left to right, the sides measure 15, 12, and 20 units.
Zina, weldon, delia, leisha, bento, charlotte