Which of the following statements best describes a segment of a circle

Alex drew a circle with right triangle prq inscribed in it, as shown below: the figure shows a circle with points p, q, and r on it forming an inscribed triangle. side pq is a chord through the center and angle r is a right angle. arc qr measures 80 degrees.

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Solve each quadratic equation by factoring and using the zero product property. 14x - 49 = x^2