Examples for 8th grade - page 19

  1. Hexagonal pyramid
    Hexagonal_pyramid Calculate the volume and the surface of a regular hexagonal pyramid with a base edge length 3 cm and a height 5 cm.
  2. Map
    mapa_bce Forest has an area of ​​36 ha. How much area is occupied by forest on the map at scale 1:5000?
  3. Box
    uhlopriecka Calculate the angle between box base 5 x 7 and body diagonal length 14.
  4. Balance
    balance_weight The rod are 1.7 m long hanging weights 2 kg and 12 kg on ends. Where are centre of rod (distance from weight 2 kg) to be in balance?
  5. Dices
    dices_2 We will throw two dice. What is the probability that the ratio between numbers on first and second dice will be 1:2?
  6. Root
    sq_root Use law of square roots roots: ?
  7. Event probability
    dices_1 The probability of event G in 9 independent experiments is 0.48. What is the probability that the event G occurs in one experiment (probability is same)?
  8. Height difference
    road What height difference overcome if we pass road 1 km long with a pitch21 per mille?
  9. The bridge
    circle_dam Across the circle lakepasses through its center bridge over the lake. At three different locations on the lake shore are three fishermen A, B, C. Which of fishermen see the bridge under the largest angle?
  10. Purchase
    cart Mother bought 5 boxes of milk and 7 kg of potatoes and paid a total CZK 147. Aunt bought 7 boxes of milk and 3 kg of potatoes and paid 131 CZK. What is the price of one carton of milk and 1 kg of potatoes? How CZK together would have saved if bought at the
  11. Shots
    broky 2000 lead shots with diameter 2 mm is decanted into a ball. What is it diameter?
  12. Do you solve this?
    rectangles_4 Determine area S of rectangle and length of its sides if its perimeter is 96 cm.
  13. Water inlets
    pipe Inlet valve with a flow rate of 12 liters per second is filled tank for 72 minutes. How long take to fill full tank if we open one more such valve half an hour after?
  14. Inscribed rectangle
    circle_desc_rectangular The circle area is 184. Determine the area of inscribed rectangle with one side 10 long.
  15. Workers
    jumps Workers digging a jump pit in the school yard. Pit has a cuboid shape with a length 20 m, a width 20 dm and depth 36 cm. They excavate 0.4 cubic meters of soil an hour. How much time (hours and minutes) is need to the excavate this pit?
  16. Sales vs profit
    Acer+vs+Apple Apple sells 45 percent less computes than the Acer but the profit from their sales is 1.7 times higher than Acer. How many times are Apple computer more expensive than Acer?
  17. Intersections
    intersect_circles How many intersections have circles with radius 12 dm and 17 dm, if the distance of their centers is 20 dm.
  18. Circumscribing
    thales Determine the radius of the circumscribed circle to the right triangle with legs 3 cm and 3 cm.
  19. Euler problem
    euler Someone buys a 720 tolars towels. If it was for the same money of 6 more towels, it would be 6 tolars cheaper each. How many were towels?
  20. Felix
    astronaut Calculate how much land saw Felix Baumgartner after jump from 22 km above ground. The radius of the Earth is R = 6378 km.

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