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Ede4ka [16]
3 years ago
5

a solid pyramid with a square base with side 12 cm and height 25 cm is made of metal. The metal is melted to form spherical ball

bearings of radius 7 mm. How many pyramids are needed to form 2490 ball bearings?​
Mathematics
1 answer:
dangina [55]3 years ago
7 0

Answer:

3 pyramids.

Step-by-step explanation:

The volume of one pyramid is 1/3 * b^2 * h

= 1/3 * 12^2 * 25

= 1200 cm^3.

The volume of one ball bearing = 4/3 * π * 0.7^3

= 1.43676 cm^3.

Therefore the volume of 2490 ball bearings = 2490 * 1 .43676

= 3577.53 cm^3.

So we need 3577.53 / 1200 = 2.98 = 3 pyramids.

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7 (sin(19<em>x</em> + 39<em>x</em>) + sin(19<em>x</em> - 39<em>x</em>)) = 14 cos(39<em>x</em>) sin(19<em>x</em>)

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