On a coordinate plane, a line goes through points (0, 0) and (1, 3). Based on the graph, what is the constant of variation?

Barbara's piano instructors house is 7 1/8 miles from her house. after biking for 1 3/4 miles she stops to rest how much longer does she need to bike to reach her instructor's house

The volume of gas a balloon can hold varies directly as the cube of its radius. imagine a balloon with a radius of 3 inches can hold 81 cubic inches of gas. how many cubic inches of gas must be released to reduce the radius down to 2 inches?

Find the volume of the solid obtained by rotating the region enclosed by the curves y=1x and y=7^-x about the x-axis. (use symbolic notation and fractions where needed.) volume =