The sum of the measures of the interior angles of a polygon is 1620°. How many sides does the polygon have?
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The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

In each diagram, line p is parallel to line f, and line t intersects lines p and f. based on the diagram, what is the value of x? ( provide explanation)

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi, r^3 , where r is the sphere’s radius.