Examples for 8th grade - page 7

  1. Maximum area of rhombus
    rhombus Calculate the interior angles at which equilateral rhombus has maximum area.
  2. Barrel of oil
    dieselbarrel Barrel of oil weighs 253 kg. When it mold 43% oil, weighed 159 kg. What is the mass of the empty barrel?
  3. Cone
    cones Circular cone of height 15 cm and volume 10598 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.
  4. Rectangle
    rectangle_ABCD In rectangle ABCD with sides |AB|=19, |AD|=16 is from point A guided perpendicular to the diagonal BD, which intersects at point P. Determine the ratio ?.
  5. Pediatrician
    doctor Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work?
  6. Rhombus and inscribed
    rhombus_2 Rhombus has side a = 42 cm, the radius of the inscribed circle is r = 18 cm. Calculate the length of its two diagonals.
  7. Expansion
    magnification If one side of the rectangle is larger 4-times and second 2-times, what percentage increases the area of rectangle?
  8. Radians
    pi_text Convert 270° to radians. Write result as multiple of number π.
  9. Cube zoom
    krychle_1 How many percent we increase volume and surface of cube, if we magnify its edge by 38%.
  10. Tangents
    tangents To circle with a radius of 41 cm from the point R guided two tangents. The distance of both points of contact is 16 cm. Calculate the distance from point R and circle centre.
  11. Rectangle - sides ratio
    rectangle_2 Calculate area of rectangle whose sides are in ratio 3:13 and perimeter is 673.
  12. Cu thief
    trolleywire_1 The thief stole 122 meters copper wire with cross-section area of 95 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. Daily average
    weather_forecast Calculate the average temperature during the day, when 13 hours was 22 °C and 11 hours was 17 °C.
  14. Arc
    arc_1 Circle arc corresponding to angle is 32° is 28 dm long. What is the length of the entire circle?
  15. Lathe
    soustruh From the cube of edge 37 cm was lathed maximum cylinder. What percentage of the cube is left as waste after lathed?
  16. Sea water
    sea Mixing 94 kg of sea water with 82 kg rainwater is created water containing 4.2% salt. How many percent sea water contains salt?
  17. Pedestrian up-down hill
    peak Pedestrian goes for a walk first at plane at 4 km/h, then uphill 3 km/h. Then it is in the middle of the route, turns back and goes downhill at speed 6 km/h. Total walk was 6 hours. How many kilometers went pedestrian?
  18. Medians
    medias_triangle Calculate the sides of a right triangle if the length of the medians to the legs are ta = 21 cm and tb=12 cm.
  19. Kites
    drake Boys run kite on a cable of 68 meters long. What is the kite altitude, if the angle from the horizontal plane is 72°?
  20. Described
    desc_circle Calculate perimeter of the circle described by a triangle with sides 478, 255, 352.

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