1957 AHSME Problems/Problem 48
Problem
Let be an equilateral triangle inscribed in circle
.
is a point on arc
.
Lines
,
, and
are drawn. Then
is:
Solution
Since quadrilateral is inscribed in circle
, thus it is a cyclic quadrilateral. By Ptolemy's Theorem,
Because
is equilateral, we cancel out
,
, and
to get that