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The base of the pyramid is 100 blocks by 100 blocks; each successive layer is one less block wide and deep, until the top layer which is simply one block. Each block is 97 cm wide by 97 cm deep by 63 cm tall.

If one liter of paint can coat exactly three square meters, how many liters are required to coat the entire exposed surface of the pyramid? Round up to the nearest liter.

I know what to do but is there a "pattern" that can be used here?

EDIT:

Paint Used For Side of Blocks:

1+2+3...+100

= 5050 x width of 97 x height of 63 x 4 sides of a pyramid

= 123,442,200 cm2 / 10 000

= 12,344.22 m2 / 3

= 4114.74 litres of paint

Paint Used For Top of Blocks:

1+2+3...+100

= (100 x 100) (97 x 97)

= 94090000 cm2 / 10 000

= 9409 m2 / 3

= 3136.33

Total:

4114.74 + 3136.33

= 7251.07

= 7251 L.

Can I have confirmation that this is right? =)

If one liter of paint can coat exactly three square meters, how many liters are required to coat the entire exposed surface of the pyramid? Round up to the nearest liter.

I know what to do but is there a "pattern" that can be used here?

EDIT:

Paint Used For Side of Blocks:

1+2+3...+100

= 5050 x width of 97 x height of 63 x 4 sides of a pyramid

= 123,442,200 cm2 / 10 000

= 12,344.22 m2 / 3

= 4114.74 litres of paint

Paint Used For Top of Blocks:

1+2+3...+100

= (100 x 100) (97 x 97)

= 94090000 cm2 / 10 000

= 9409 m2 / 3

= 3136.33

Total:

4114.74 + 3136.33

= 7251.07

= 7251 L.

Can I have confirmation that this is right? =)

Last edited: