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Direct Proportionality Question!!

A, r and T are three variables.
A is proportional to T2 A is also proportional to r3 T = 47 when r = 0.25
Find r when T = 365 Give your answer correct to 3 significant figures.
Reply 1
Original post by daniel111_ok
A, r and T are three variables.
A is proportional to T2 A is also proportional to r3 T = 47 when r = 0.25
Find r when T = 365 Give your answer correct to 3 significant figures.

If x prop. y and x prop. z then y prop. z.

E.g. Number of cakes is proportional to amount of flour and number of eggs.

--> Number of eggs is proportional to amount of flour.
Ok I know that, but what do I do?
Original post by daniel111_ok
Ok I know that, but what do I do?


So T squared is directly proportional to r cubed; how can you write that as an equation?
Original post by Muttley79
So T squared is directly proportional to r cubed; how can you write that as an equation?


t^2=r^3
Original post by daniel111_ok
t^2=r^3


You need to include a constant (usually we use k) in the equation - then substiitute in the given information to calculate it.
what was the answer ?

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