A semi-circular stage has a diameter of 20m. What is the area of the stage?

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?

Which is f(5) for the function –2x2 + 2x - 3?

This is a map of the mars exploration rover opportunity predicted landing site on mars. the scale is 1cm : 9.4km. what are the approximate measures of the actual length and width of the ellipse? i mostly need to know how to set it up : )