Answer:
∠C = 80 ° ; ∠ T = 40°.
Step-by-step explanation:
Triangle CRS is isosceles because it has two sides of equal length. (CR and CS are radii).
An isosceles triangle has also two equal angles, which means that ∠CRS= ∠CSR.
Therefore, ∠C = 80 ° (180° – 50° - 50°) because the sum of angles in a triangle is 180 degrees.
∠C is the central angle of the arc RS.
∠ T is the inscribed angle of the arc RS.
An inscribed angle is half of a central angle that subtends the same arc on the circle, so the inscribed angle ∠ T is half of the central angle ∠C. Since ∠C = 80 °, we can easily determine the measure of ∠ T:
80° divided by 2 is 40°.
