M is directly proportional to r cubed. When r=4, M=160. A) Work out the value of M when r=2. B) Work out the value of r when M=

Question

M is directly proportional to r cubed. When r=4, M=160.
A) Work out the value of M when r=2.
B) Work out the value of r when M=540.

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Thanh Hà 3 months 2021-08-19T05:38:51+00:00 1 Answers 0 views 0

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    2021-08-19T05:40:35+00:00

    Answer:

    A. M= 20

    B. r = 6

    Step-by-step explanation:

    M=kr³

    where k is the constant

    M= 160 , r 4

    160= k(4)³

    k = 160/4³= 2.5

    A. when r= 2 , M= kr³

    M= 2.5(2)³ = 20

    B. when M= 540, find r

    M= kr³

    r³ = M/k

    r³ = 540/2.5

    r³= 216

    r = 6

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