Round 2,990,000 to the nearest tenth

Ineed with angles and the measure of them i have abc a is 65 and b is (3x-10) and c is (2x) find the value of x

What is the inverse of f(x) = 6x -24

Adolphin is swimming with her friend. the dolphin jumps to a height of 4.54.54, point, 5 meters above the surface of the water as her friend swims 9.89.89, point, 8 meters directly below her. what is the position of the dolphin's friend relative to the surface of the water? meters