Examples for 8th grade - page 54

  1. 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?
  2. Tiles
    wall-tiles-img-5 How many square tiles with the content 121 cm2 has to be ordered for the paving of the square room with a side length of 2.75 meters?
  3. Tetrahedral pyramid
    jehlan_1 Calculate the volume and surface area of a regular tetrahedral pyramid, its height is $b cm and the length of the edges of the base is 7 cm.
  4. Three co-owners
    pracovnici The three co-owners of building company have earnings from a contract portioned in the ratio of 3:6:7. Each of them received the amount in whole USD. One of them on contract earned 86450 USD. What was the total earnings this order?
  5. School year
    boys_girls At the end of the school year has awarded 20% of the 250 children who attend school. Awat got 18% boys and 23% of girls. Determine how many boys and how many girls attend school.
  6. Legs
    zidle In the room are four-legged chairs, three-legged stool, and all are sitted with (one) people. I counted all the leg room and there were a total of 39. How many are there chairs, stool and people?
  7. Internal angles
    angle_3 One internal angle of the triangle JAR is 25 degrees. The difference is the size of the two other is 15°. Identify the size of these angles.
  8. Painting
    natieranie Jožko with Fero painted the bench for four hours. How many hours would take work if four friends help him?
  9. Painters
    maliri 15 painters painted fence for 280 minutes. For how many minutes paint half of this fence 12 painters?
  10. Uranium ore
    uran Uranium ore contains 0.2% of pure uranium and pure uranium contains 0.07% of fissile uranium. How many grams of fissile uranium contains 2200 ton of uranium ore?
  11. Triangle
    Triangle_trig Calculate the sides of the triangle if its area S = 630 and the second cathethus is shorter by 17.
  12. ISO triangle
    rr Calculate the area of an isosceles triangle KLM if the length of its sides are in the ratio k:l:m = 4:4:3 and has perimeter 128 mm.
  13. Parcel
    land_parcel Both dimensions of the rectangular parcel were increased by 40%. By how many % has increased its acreage?
  14. Quadrilateral
    diamond_2 In the square ABCD point P is in the middle of the DC side and point Q in the middle pages AD. If the area of quadrilateral BQPC is 96 cm2, what is the area of ABCD?
  15. Sales off
    save_now Calculate what was the original price of the good, if the price after discount 40% and the subsequent rise of 30% is 4000 USD.
  16. Diamond
    diamond_1 Rhombus has side 23 cm and and one of diagonal 36 cm long. Calculate its area.
  17. Trapezoid ABCD v2
    trapezium_table Trapezoid ABCD has length of bases in ratio 3:2. The area of riangle ACD is 956 dm2. What is the area of trapezoid ABCD?
  18. TV commercials
    ad_on_TV For the typical one-hour prime-time television slot, the number of minutes of commercials is 7/23 of the minutes of the actual program. Determine how many minutes of the program are shown in that one hour.
  19. Round table
    obrus-kruhovy Round table with diameter d = 95 cm is coated by square tablecloth with a side length 122 cm. About how many cm is higher center of tablecloth than its cornes?
  20. Slope of the pool
    swimming_pool Calculate slope (rise:run) of the bottom of swimming pool long 40 m. Water depth at beginning of pool is 1.15 m (for children) and depth at end is 1.92 m (for swimmers). Slope express as percentage and as angle in degrees.

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