Careful! Duck!

Calculus Level 3

Min, the perfectly spherical duck, is happily picking up cubical seeds to eat. He grows in volume at a rate of 9 cubic feet per day. When Min's radius is 7 feet, at what rate (in square feet per day) is his surface area growing at that instant?

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Careful! Duck!

Excel in math and science

Master concepts by solving fun, challenging problems.

It's hard to learn from lectures and videos

Learn more effectively through short, interactive explorations.

Used and loved by over 5 million people

Learn from a vibrant community of students and enthusiasts, including olympiad champions, researchers, and professionals.

Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.

Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.