What does r equal in this problem 0.3r = 2.1

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

The length of triangle base is 26. a line, which is parallel to the base divides the triangle into two equal area parts. find the length of the segment between triangle legs.

F(x) = 1/x g(x)=x-4 can you evaluate (g*f)(0) ? why or why not?