Examples for 8th grade - page 7

  1. Railways
    railways Railways climb 5.8 ‰. Calculate the height difference between two points on the railway distant 2389 meters.
  2. Cone
    cones Circular cone of height 16 cm and volume 5024 cm3 is at third of the height (measured from the bottom) cut plane parallel to base. Calculate the radius and circumference of the circular cut.
  3. Ravens
    krkavec The tale of the Seven Ravens were seven brothers, each of whom was born exactly 1.5 years after the previous one. When the eldest of the brothers was 4-times older than the youngest, mother all curse. How old was seven ravens brothers when their mother cur
  4. Radians
    pi_text Convert 54° to radians. Write result as multiple of number π.
  5. Expansion
    magnification If one side of the rectangle is larger 3-times and second 4-times, what percentage increases the area of rectangle?
  6. Arc
    arc_1 Circle arc corresponding to angle is 193° is 23 dm long. What is the length of the entire circle?
  7. Car
    american-cars Car goes from point A to point B at speed 70 km/h and back 76 km/h. If they goes there and back at speed 73 km/h trip would take 19 minutes shorter. What is distance between points A and B?
  8. Tangents
    tangents To circle with a radius of 98 dm from the point A guided two tangents. The distance of both points of contact is 155 dm. Calculate the distance from point A and circle centre.
  9. Rectangle
    rectangle_ABCD In rectangle ABCD with sides |AB|=11, |AD|=12 is from point A guided perpendicular to the diagonal BD, which intersects at point P. Determine the ratio ?.
  10. Maximum area of rhombus
    rhombus Calculate the interior angles at which equilateral rhombus has maximum area.
  11. Barrel of oil
    dieselbarrel Barrel of oil weighs 238 kg. When it mold 20% oil, weighed 196 kg. What is the mass of the empty barrel?
  12. Cu thief
    trolleywire_1 The thief stole 121 meters copper wire with cross-section area of 101 mm2. Calculate how much money gets in the scrap redemption, if redeemed copper for 5.5 eur/kg? The density of copper is 8.96 t/m3.
  13. Lathe
    soustruh From the cube of edge 52 cm was lathed maximum cylinder. What percentage of the cube is left as waste after lathed?
  14. Described
    desc_circle Calculate perimeter of the circle described by a triangle with sides 418, 59, 430.
  15. Daily average
    weather_forecast Calculate the average temperature during the day, when 14 hours was 20 °C and 10 hours was 15 °C.
  16. Rhombus and inscribed
    rhombus_2 Rhombus has side a = 72 cm, the radius of the inscribed circle is r = 10 cm. Calculate the length of its two diagonals.
  17. Medians
    medias_triangle Calculate the sides of a right triangle if the length of the medians to the legs are ta = 23 cm and tb=14 cm.
  18. Rectangle - sides ratio
    rectangle_2 Calculate area of rectangle whose sides are in ratio 1:7 and perimeter is 735.
  19. Pediatrician
    doctor Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work?
  20. Cube zoom
    krychle_1 How many percent we increase volume and surface of cube, if we magnify its edge by 61%.

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