In the circle below, AB is parallel to CD, AD is a diameter of the circle, and AD = 36.What is the length of AB? Express your answer in terms of pi.

codehtml127
Jun 23, 2018

#1**+1 **

Since AD is a diameter, then ABD will form a right triangle with angle ABD = 90°

So...angle ADB = 40°

And we can find AB as :

sin (40) = AB / 36

AB = 36 * sin (40) = 23.140353948732 ≈ 7.3658 pi units

CPhill
Jun 24, 2018