Cube, Cuboid, Prism and Cylinder

1. State the basic formulas for calculating volume and surface area:

  • cube
  • cuboid (rectangular prism)
  • prism
  • cylinder
Solution:

Cube

a – edge of the cube

volume V = a3

surface area S = 6a2

kocka1a

Cuboid

a, b, c – edges of the cuboid

volume V = a·b·c

surface area S = 2(ab+ac+bc)

kocka1b

Prism

Sp – area of the base
Q – lateral area
v – height of the prism

volume V = Sp·v

surface area S = 2Sp + Q

Cylinder

r – radius of the base
v – height of the cylinder

volume V = π·r2·v

surface area S = 2πr(r+v)

Q = 2πrv

2. Two cube-shaped crates with edges a = 70 cm, b = 90 cm are to be replaced by one cube-shaped crate.

What will be its edge length?
Solution:

kocka2

The edge of the replacement cube will be c = 102.3 cm.

3. The edge of the second cube is 2 cm larger than the edge of the first cube. The difference of the cubes’ volumes is 728 cm3.

Calculate the edge lengths of both cubes.
Solution:

Edge of the first cube: x
Edge of the second cube: x + 2

kocka3

The edge of the first cube is 10 cm, of the second 12 cm.

4. A cube with edge a is given. Known values are in the table.

Complete the table!

kocka4
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5. The edges of two cubes differ by 22 cm. Their surface areas differ by 19,272 cm2.

Determine the edges of both cubes.
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6. A cuboid has dimensions a = 4 cm, b = 3 cm, c = 5 cm.

Calculate the angle α between the base diagonal and the space diagonal.
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7. The surface area of a cuboid is S = 376 cm2. Its edges are in the ratio a:b:c = 3:4:5.

Calculate the volume of this cuboid.
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8. A water tank in the shape of a cuboid contains 1500 hl of water; the water height is 2.5 m.

Determine the base dimensions if one dimension is 4 m greater than the other.
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9. Calculate the volume of a cuboid if its base has S1 = 272 cm2 and the lateral faces have S2 = 240 cm2, S3 = 255 cm2.

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10. What is the mass of an iron rod (ρ = 7800 kg·m-3) that is 1.5 meters long and has a square cross-section with side a = 45 mm?

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11. The base of a right triangular prism is a right triangle with legs a = 9 cm, b = 12 cm. The height of the prism is twice the hypotenuse of the right-angled base.

Calculate the volume and surface area of the prism.
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12. How much soil must be moved when digging a straight trench 170 m long, whose cross-section is an isosceles trapezoid with bases a = 150 cm, c = 80 cm and height v = 83 cm?

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13. Calculate the volume and surface area of a prism whose base is a rhombus with diagonals u1 = 12 cm, u2 = 16 cm. The height of the prism equals twice the base edge.

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14. The table lists quantities characterizing various cylinders.

Complete the table!

kocka14
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15. The lateral surface of a right circular cylinder, developed into a plane, is a square with area a2 = 81 cm2.

Determine the base radius r, the height of the cylinder v, and its volume V.
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16. An equilateral cylinder (v = 2r) has volume V = 250 cm3.

Calculate the surface area of this solid.
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17. An aluminum wire (ρ = 2.7 g·cm-3) with diameter d = 3 mm has total mass m = 1.909 kg.

Determine the length of the wire l.
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18. The outer circumference of a brass tube (ρ = 8.5 g·cm-3) is 31.4 cm. Its mass is 3.14 kg and its length is 60 cm.

What is the wall thickness of the tube?
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