Examples for 8th grade - page 42

  1. Roots
    square_roor Calculate the square root of these numbers:
  2. Tank No 8
    tank1 Tank is filled by one inlet valve with a flow rate of 12 liters per second in 72 minutes. How long take the tank to fill, if we open half an hour after one more inlet?
  3. Bottle
    bottle Bottle with wine costs 61 USD. Wine is 11 USD more expensive than the empty bottle. How much is the bottle itself?
  4. Tetrahedral prism
    hranol_1 The height of a regular tetrahedral prism is three times greater than the length of the base edge. Calculate the length of the base edge, if you know that the prism volume is 2187 cm3.
  5. Water level
    hladina.JPG How high reaches the water in the cylindrical barell with a diameter of 12 cm if there is a liter of water? Express in cm with an accuracy of 1 decimal place.
  6. Tree
    strom How tall is the tree that observed in the visual angle of 52°? If I stand 5 m from the tree and eyes are two meters above the ground.
  7. Water pool
    basen_2 Pool with volume 990hl completely filled, if water flows by one tap 8 hours and by second tap 6 hours. First tap give 10hl more than second per hour. How many hl flows in each of them in an hour?
  8. Deposit 3
    interest_money After a year had Martin on bank account € 1764. What was the interest rate when the initial deposit was € 1581?
  9. Sheep
    ships Shepherd tending the sheep. Tourists asked him how much they have. The shepherd said, "there are fewer than 500. If I them lined up in 4-row 3 remain. If in 5-row 4 remain. If in 6-row 5 remain. But I can form 7-row." How many sheep have herdsman?
  10. Moon
    zem_mesic We see Moon in the perspective angle 28'. Moon's radius is 1740 km at the time of the full moon. Calculate the mean distance of the Moon from the Earth.
  11. Garden pool
    basen_1 Mr. Novak fill garden pool (cylinder; diameter of 200 cm) with 31.4 hl of water. What is the depth of the pool when the water level is 10 cm below the upper edge of the pool?
  12. Diamond
    diamond_1 Rhombus has side 23 cm and and one of diagonal 36 cm long. Calculate its area.
  13. Slope
    lines.JPG Calculate the slope of a line that intersects points (38,-23) and (-93,5).
  14. Decomposition
    prime_factorization Make decomposition using prime numbers of number 355. Result write as prime factors (all, even multiple)
  15. 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?
  16. Lamp cone
    lampa Calculate the surface of a lamp shade shaped of a rotary truncated cone with base diameter 32 cm and 12 cm and height 24 cm.
  17. Rectangle and circle
    rectangle_circle_desc The rectangle ABCD has side lengths a = 40 mm and b = 30 mm and is circumscribed by a circle k. Calculate approximately how many cm is circle long.
  18. Aquarium 6
    water_aquarium How high is the water level in the aquarium with a rectangular base 40cm and 50cm if it is filled 0,65hl of water?
  19. Percentage of waste
    14 In a square plate with side 42 cm we cut 4 same circles. Calculate the percentage of waste.
  20. Lie/do not lie
    lines_and_points The function is given by the rule f(x) = -x-12. Determine whether point D[-4; 2] lies on this function. Solve graphically or numerically and give reasons for the your answer.

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