Examples for 8th grade - page 29

  1. Cuboid 5
    drevo_1 Calculate the weight of the cuboid with dimensions of 12 cm; 0.8 dm and 100 mm made from spruce wood (ς = 550 kg/m3).
  2. Strawberries
    strawberries Father collects strawberries himself in 4 hours, son in 10 hours. How long will it take them along when dad comes to help son collect strawberries after 4 hours?
  3. Crown
    2_kcs Siblings collect a 2-crowns and 5-crowns. Together have 80 coins with a total of value 310 crowns. How many saved two-crowns and how many five-crowns?
  4. Father and son
    father_sin Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son?
  5. Painter 3
    painter_2 Dad want to paint wall high 250 cm wide and 230 cm with wallpaper. How many meters must buy wallpaper if wallpaper width is 60 cm?
  6. Chicken
    sliepka I threw three chicken for a handful of grains and I noticed that it eat in a ratio of 8:7:6 and two of them grabbed 156 grains. How many grains have fought that chicken?
  7. SAS triangle
    triangles2 The triangle has two sides long 7 and 19 and included angle 144°11'59″. Calculate area of this triangle.
  8. 30-60-90
    30-60-90 The longer leg of a 30°-60°-90° triangle measures 7. What is the length of the shorter leg?
  9. RT and ratio
    triangles Right triangle whose cathetus are in a ratio 6:17 has hypotenuse 47 m long. How long are cathetus?
  10. Revenue
    odmena Mr. Robert and Mr. Norbert get together € 1400. The revenue split in the ratio of 4:3, depending upon each work. How many got each of them?
  11. Trapezoid
    hexphitri Area of trapezoid is 135 cm2. Sides a, c and height h are in a ratio 6:4:3. How long are a,c and h? Make calculation...
  12. Water
    storm_1 On the lawn which has area 243 m2 rained 5 mm of water. How many liters of water rained?
  13. Quadrangular prism
    trapezium_prism The quadrangular prism has a volume 648 cm3. Trapezoid which is its base has the dimensions bases: a = 10 cm, c = 5 and height v = 6 cm. What is the height of the prism?
  14. Flowerbed 2
    flowerbed Around the square flower bed in a park is sidewalk 1.4 m wide. The area of ​​this sidewalk is 125 m2. What is the area of the flowerbed?
  15. Circle sector
    vysec Circular sector with a central angle 10 ° has area 254 cm2. Calculate its radius r.
  16. Rectangular trapezoid
    rt_licho The rectangular trapezoid ABCD is: /AB/ = /BC/ = /AC/. The length of the median is 6 cm. Calculate the circumference and area of a trapezoid.
  17. Pyramid
    3d_shapes Cuboid ABCDEFGH has dimensions AB 3 cm, BC 4 cm, CG 5 cm. Calculate the volume and surface area of a triangular pyramid ADEC.
  18. Field with vegetables
    irrigation Field planted with vegetables has shape of a rectangular isosceles triangle with leg length of 24 m. At the vertices of the triangle are positioned rotating sprinklers with a range of 12 m. How much of the field sprinkler doesn't irrigated?
  19. Number
    sqrt_2 Is number 4.764023 irrational?
  20. Trapezoid ABCD
    trapezoid_2 Calculate the perimeter of trapezoid ABCD if we know the side c=25, b=16 which is also a height and side d=27.

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