What is the measure (in radians) of central angle Θ in the circle below?

In triangle abc segment de is parallel to the side ac . (the endpoints of segment de lie on the sides ab and bc respectively). find de, if ac=20cm, ab=17cm, and bd=11.9cm;

On saturday morning, calls arrive at ticketmaster at a rate of 108 calls per hour. what is the probability of fewer than three calls in a randomly chosen minute?

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left