+184 Two circles of radius 10 cm overlap such that each circle passes through the center of the other, as shown. How long, in cm, is the common chord (dotted segment) of the two circles? Express your answer in the simplest radical form.
+150 
Here is the picture
\(\angle A=\angle B=\angle C=60^\circ \)
tringangle ABC is an equilateral triangle because AC, AB, BC are all radius, so the length is same
The length of the common chord :
\(2\times \sqrt{10^2-5^2}=2\times 5\sqrt{3}=10\sqrt{3}\)
