The measure of the third angle is 50 because a triangle has a sum of 180 degrees by angle.
so... 46+84=130 and to get to 180, the last angle has to be worth 50.
Point estimate proportion is the average of lower and upper interval limit.
Point estimate proportion )p) = x/n
Where x = observations, n=sample size
Substituting;
p= 40/493 = 0.0811