Examples for 8th grade

  1. Rotating cone
    kuzel_3 Calculate the volume and the surface area of a rotating cone of base radius r = 2.3 dm and a height h = 46 mm.
  2. Pyramid 4sides
    pyramid_2 Calculate the volume and the surface of a regular quadrangular pyramid when the edge of the base is 4 cm long and the height of the pyramid is 7 cm.
  3. Cube diagonals
    krychlicka_1 Determine the volume and surface area of the cube if you know the length of the body diagonal u = 216 cm.
  4. Roof 8
    veza_1 How many liters of air are under the roof of tower which has the shape of a regular six-sided pyramid with a 3,6-meter-long bottom edge and a 2,5-meter height? Calculate the supporting columns occupy about 7% of the volume under the roof.
  5. Sputnik
    sputnik The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round?
  6. Pyramid
    jehlan_4b_obdelnik The pyramid has a base rectangle with a = 6cm, b = 8cm. The side edges are the same and their length = 12.5 cm. Calculate the surface of the pyramid.
  7. Folded square
    square_folded ABCD is a square. The square is folded on the midpoint of AB and A is folded onto the fold, creating a shaded region. The perimiter of the shaded figure is 75. Find the area of square ABCD
  8. Cuboid and ratio
    kvader Cuboid has dimensions in ratio 1:2:6 and the surface area of the cuboid is 1000 dm2. Calculate the volume of the cuboid.
  9. Cylindrical tank
    valec_7 Cylindrical tank holds 600hl water and is deep 2.5 m. Calculate the diameter of the cylinder.
  10. Hexagonal pyramid
    jehlan_6 Regular hexagonal pyramid has dimensions: length edge of the base a = 1.8 dm and the height of the pyramid = 2.4 dm. Calculate the surface area and volume of a pyramid.
  11. Potatoes bags
    vrece_zemiakov I have three bags with 21 kg potatoes. The first bag is 5.5 kg more than in the second bag and the third is 0.5 kg more than in the second bag. Determine how many kgs of potatoes is in each bag.
  12. Regular triangular prism
    3b_hranol Calculate the surface area of body of regular triangular prism, when the length of its base edge is 6.5 cm and height 0.2 m.
  13. Tree shadow 3
    stromy_1 What is the diameter of a tree around which is 3m 9dm 7cm long rope wrapped? How big is its cross-sectional area?
  14. Sawmill factory
    rj Peter works in the factory. The bus stop is 10 km from the factory. Therefore, always when the bus arrives for Peter, the driver leaves factory and takes him to work. They are coming at the saw exactly at 8:00. Today the bus arrived 11 minutes earlier and
  15. Alcohol mixture
    roztoky_1 From 55% and 80% alcohol we have to produce 0.2 kg of 60% alcohol. How many of them do we use in solution?
  16. Water reservoir
    vodojem The reservoir shape of a cylinder having a diameter 8 m and a height 2.8 m. The device indicates that the reservoir contains 800 hectoliters of water. Calculate how much % of volume is used.
  17. Price increase
    sleva A 20 percent price increase meant a 90-crown raise. How many cost a product after?
  18. Gasoline tank cylindrical
    cisterna What is the inner diameter of the tank, which is 8 m long and contains 40 cubic cubic meters of gasoline?
  19. Collection
    maliny_1 John has collected half a bucket of raspberries in 45 minutes, Eva collects the whole bucket in an hour. How many minutes it would take to fill a bucket if the two children work together?
  20. Scale of map
    map_9 James travels one kilometer in 12 minutes. The route walked for half an hour measured on the map 5 cm. Calculate how many kilometers James walked for half an hour. Find the scale of the map.

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