A petroleum refinery needs to empty a spherical storage tank of radius 9 m. The contents will be
transferred to cylindrical tanks of radius 4 m and height 20 m. What is the minimum number of cylindrical
tanks that must be available in order to empty the entire spherical tank?

it is true

step-by-step explanation:

all the combinations add up i used   calculator

a variable is any characteristics, number, or quantity that can be measured or counted. a variable may also be called a data item. hope i !

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step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -