What is the difference between a simple machine and a mechanism?

The blue segment below is a diameter of oo. what is the length of the radius of the circle?

If we review the changes in the landscape surrounding the great salt lake in utah we can see a change in topography. look at the area to the south of the lake. what change has occurred during the last twenty-nine years? a) erosion of the hills b) an increase in marshland c) flooding of the area and the development of wetlands d) deposition of sediments and an increase in elevation

The volume of the triangular prom is 54 cubic units