1971 AHSME Problems/Problem 5
Problem 5
Points , and
lie on the circle shown and the measures of arcs
and
are
and
respectively. The sum of the measures of angles
and
is
Solution
We see that the measure of equals
, and that the measure of
equals
.
Since
, the sum of the measures of
and
is $\widehat{BD} \div 2 = 80^{\circ} \div 2 = 40^{\circ} \Longrightarrow \textbf{(C) }.