SOLUTION: the amount of material needed to cover a ball is directly proportional to the square of its diameter. a ball with a diameter of 12 cm needs 452 cm(squared) of materail to cover it

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Question 192820This question is from textbook algebra structure and method
: the amount of material needed to cover a ball is directly proportional to the square of its diameter. a ball with a diameter of 12 cm needs 452 cm(squared) of materail to cover it. if 1017 cm(squared) of material is to be used what is the diameter of the ball. This question is from textbook algebra structure and method

Answer by Mathtut(3670) About Me  (Show Source):
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let amount of materal be a and let the diameter be d
:
a%2Fd%5E2=k where k is the constant of variation
:
452%2F12%5E2=k k=3.14
:
1017%2Fd%5E2=3.14 --->d%5E2=1017%2F3.14-->d%5E2=323.89
:
d=sqrt%28323.89%29=18 cm