⇒Sum of all the three interior angles of a triangle is 180°
⇒This means that the sum of the first angle, second angle and third angle is 180°
let the third angle which is unknown be x.
36.6°+59.3°+x=180°
95.9°+x=180°
x=180°-95.9°
x=84.1°
∴The measure of the third angle is 84.1°