Simplify 2.79569892473 to the nearest hundredth

The ph level of a blueberry is 3.1 what is the hydrogen-ion concentration [h+] for the blueberry

Plz hurry finals a paper cup in the shape of an inverted cone is 8 inches tall and has a radius of 1.5 inches. how much water can the cup hold? use 3.14 for pi. round the answer to the nearest tenth. a) 12.6 cubic in. b) 18.8 cubic in. c) 37.7 cubic in. d) 56.5 cubic in.

Solve the system of equations. y=3x-1 and y=-2x+9. show work