Can someone help me in this one :)

What is the length x of the side of the triangle below? (hint: use the cosine function)

Apebble is thrown into a calm lake, ripples are formed from the center and move outward. the water particles in the lake travel in a circular pattern that moves up and down on the surface of a lake, and the energy travels a) diagonally. b) downward. c) horizontally. d) upward.

Aball has an initial velocity of 3 m/s. if there is no friction, what is the highest it could roll?