Examples for 8th grade - page 13

  1. n-gon II
    x-gon_1 What is the side length of the regular 9-gon circumscribed circle of radius 13 cm?
  2. Estate
    semicircle Semicircle estate must be fence. The straight section has 44 meters long fence. How many meters of fence should buy?
  3. Road embankment
    nasyp_cesta Road embankment has a cross section shape of an isosceles trapezoid with bases 9 m and 12 m, and 4 m long leg. How many cubic meters of soil is in embankment length of 758 meters?
  4. Vinegar
    vinegar We must dilute 80 liters of 7.6% aqueous vinegar to 4.2% one. How much water is necessary to add?
  5. Square 2
    square_ABCD_1 Points D[9,-1] and B[3,3] are opposed vertices of the square ABCD. Calculate area of the square ABCD.
  6. Stairway
    steps What angle rising stairway if step height in 17 cm and width 24 cm?
  7. Canopy
    cone-roof Mr Peter has metal roof cone shape with a height of 36 cm and radius 73 cm over well. He needs paint the roof with anticorrosion. How many kg of color must he buy if the manufacturer specifies the consumption of 1 kg to 2.1 m2?
  8. Plan of the village
    mapa_1 Plan of the municipality in 1:1000 scale has plotted garden with dimensions 25 mm and 28 mm. Determine the area of gardens in ares in reality.
  9. Octahedron - sum
    8sten On each wall of a regular octahedron is written one of the numbers 1, 2, 3, 4, 5, 6, 7 and 8, wherein on different sides are different numbers. For each wall John make the sum of the numbers written of three adjacent walls. Thus got eight sums, which also.
  10. Prism
    prism_rhombus_1 Calculate the volume of the rhombic prism. Base of prism is rhombus whose one diagonal is 39 cm and the edge of the base is 24 cm. The edge length of the base of the prism and height is 3:2.
  11. Climb
    scenic_road Road has climbing 1:23. How big is a angle corresponds to this climbing?
  12. n-gon
    ngon_1 Gabo draw n-gon, which angles are consecutive members of an arithmetic sequence. The smallest angle is 70° biggest 170°. How many sides have Gabo's n-gon?
  13. OK circle
    circles2 Calculate the radius (circumradius) of the circle described right triangle with hypotenuse long 43 and one cathetus long 21.
  14. Unknown x
    UnknownX If we add to unknown number 72, then divide by 2 and then subtract 29, we get back an unknown number. What is this unknown number?
  15. Motion
    bus_1 From two different locations distant 104 km started against car and bus. The car started at 5:30 with average speed 58 km/h. Bus started at 6:40 with average speed 79 km/h. When they meet? How many kilometers went the bus?
  16. Pyramid a+h
    jehlan_1 Calculate the volume and surface area of the pyramid on the edge and height a = 26 cm. h = 3 dm.
  17. Rotary cone
    cone_2 Rotary cone whose height is equal to the circumference of the base, has a volume 4772 cm3. Calculate the radius of the base circle and height of the cone.
  18. Rectangles
    rectangles How many rectangles with area 2832 cm2 whose sides is natural numbers are?
  19. Solidarity
    salt Imagine a word solidarity means that salt donation to the needy, who have neither the salt. If we take word solidarity has word base salt + gift (only in Slovakian language). Calculate how many kilos of salt sympathetic citizen "gives" government a year i
  20. Two doctors
    dr_cvach Doctor A will determine the correct diagnosis with a probability 80% and doctor B with a probability 72%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors.

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