Examples for 8th grade - page 16

  1. Posters
    posters Column with posters in the form of a cylinder is 3.3 m high and its diameter is 1.5 m. What is the content area for which it is possible to stick posters?
  2. n-gon
    x-gon What is the side length of the regular 5-gon inscribed in a circle of radius 11 cm?
  3. Stock market
    money_1 Simon one day decided to invest € 88000 to the stock market. After six months he invested July 5 stock markets fell by 56%. Fortunately for Simon from July 5 5 to October 5 his shares have risen by 39%. Simon is then: ?
  4. Tea blend
    teas Tea blends are maked from two kinds of tea. In standard tea mixture are two teas in the ratio 1:3 and 40 g costs 42 CZK. In the premium tea mixture are weighing two teas in the ratio 1:1 and 50 grams costs 60 CZK. How much cost 10 grams of more expensive k
  5. KLMN
    trapezium In the trapezoid KLMN is given this informations: 1. segments KL and MN are parallel 2. segments KL and KM has same length 3. segments KN, NM and ML has same length. Determine the size of the angle KMN.
  6. Wood in the forest
    drevo The amount of wood in the forest was estimated at 24000 m3. How much wood will be in forest after 4 years if the annual growth of wood is 3.1% each year and logging 120 m3 each year?
  7. Barrel 3
    sud-s-vodou Barrel with water has a weight 118 kg. When we get off 75% of water it has a weight 35 kg. How many kg has empty barrel?
  8. Reservoir + water
    cuboid_water Reservoir completely filled with water weighs 13 kg. After pouring off three quarters of the amount of water weights 4 kg. Calculate the weight and volume of the reservoir.
  9. Free fall
    volny_pad Stephen fall from height 5 m. Calculate the speed he hit the ground when falling with acceleration g = 9.81 m/s2
  10. Cylinder - h
    cylinder_2 Cylinder volume is 129 cm3. Base radius is 3 cm. Calculate the height of the cylinder.
  11. Height
    thales_law Is right that in any right triangle height is less or equal half of the hypotenuse?
  12. Moving
    movie Vojta left the house at three o'clockat 4 km/h. After half hour later went from the same place Filip by bicycle at speed 25 km/h. How long take Tilip to catch up Vojta and how far from the house?
  13. Rhombus
    rhombus2 Internal angles of rhombus is in ratio 3:6. How many times is the shorter diagonal longer than side of rhombus?
  14. Train
    High-Speed-Train A passenger train traveled for 4 hours 136 km. 2.7 hours after its departure started fast train and caught it on 324 km. How many km/h is different its average speeds?
  15. Lead cube
    pb_cube Calculate the edge of the cube made ​​from lead, which weighs 11 kg. The density of lead is 11341 kg/m3.
  16. Square grid
    sit Square grid consists of a square with sides of length 1 cm. Draw in it at least three different patterns such that each had a content of 6 cm2 and circumference 12 cm and that their sides is in square grid.
  17. Playing cards
    playing_cards How many possible ways are to shuffle 7 playing cards?
  18. Division
    bonbons Three siblings Helena, Oliver and George split the bag with candies on merit in the ratio 1:6:3. How many candies should each get if in bag were 210?
  19. Triangular pyramid
    tetrahedron1 Calculate the volume and surface area of a regular triangular pyramid whose height is equal to the length of the base edges 10 cm.
  20. Wire D
    semicircle_1 Wire length 5 m is bent so that it forms a semicircle circuit (including the diameter). Determine the radius of the semicircle.

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