Nguyen is decorating the room for her sister’s baby shower party. She is wrapping Vietnamese conical hats in baby prints tissue paper to decorate the tables and some shelves in the wall. Each hat has a diameter of 16 inches and a height of 9 inches. If she wants to wrap 21 Vietnamese hats, how much tissue paper will she need?

A 4,176 in2

B 8,975 in2

C 10,580 in2

D 36,267 in2

The formula to calculate surface area of a conical hat in this case:

A = pi x radius x sqrt(radius^2 + height^2) + pi x radius^2

   = pi x (16/2) x sqrt((16/2)^2 + 9^2)) + pi x (16/2)^2

   = 503.7 (in2)

=> For 21 conical hats, Nguyen would need an amount of tissue paper:

A = 21 x 503.7 = 10577.7 (in2) = ~ 10580 (in2)

=> Option C is correct.

Hope this helps!

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Hi vọng là đáp án đúng!

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