选择题
2005 AMC 8 Problem 9: Isosceles Quadrilateral Diagonal
In quadrilateral ABCD, sides AB and BC both have length 10, sides CD and DA both have length 17, and the measure of angle ADC is 60°. What is the length of diagonal AC?
A.
13.5
B.
14
C.
15.5
D.
17
E.
18.5