posted by Priscilla .
Triangle RST, RS = 30 centimeters, measure of angle T = 105, and measure of angle R = 40. Find the area of triangle RST, to the nearest square centimeter.
Angle S is 35 degrees. (180-105-40)
Side ST's length, which I will call r, can be obtained from the law of sines.
30/sin 105 = r/sin 40 = 31.058
Therefore r = 19.96
The height measured from base RS is:
19.96 sin 35 = 11.45
Tha triangle area is
(1/2)(base)(height) = (0.5)*(30)*11.45
= 171.8 cm^2