Solve triangle. a = 33°, a = 20, b = 13

Which best explains why this triangle is or is not a right triangle?

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?

Find the value of x for which line a is parallel to line b