Examples for 8th grade - page 7

  1. Gear
    ozubene_kolesa Two gears, fit into each other, has transfer 1:5. Centres of gears are spaced 28 cm. What are the radii of the gears?
  2. Road repair
    workers_1 Road repair took 16 days for 34 workers if they worked 6 hours a day. How many days take repair same road 33 workers if they work 6 per day?
  3. Isosceles right triangle
    3triangles Calculate the area of an isosceles right triangle whose perimeter is 236 dm.
  4. Rectangle
    golden-rectangle-ratio Calculate the length of the side FL and diagonal JL of rectangle JFLB when given: |BL| = 33 cm and angle ∠ JFB = 32 degrees.
  5. Railways
    railways Railways climb 5.8 ‰. Calculate the height difference between two points on the railway distant 2389 meters.
  6. Tare
    camion Gross weight of shipment is 5073 kg and its tare is 6.9%. Calculate the net weight of the shipment.
  7. Rhombus
    rhomus_circle It is given a rhombus of side length a = 11 cm. Touch points of inscribed circle divided his sides into sections a1 = 6 cm and a2 = 5 cm. Calculate the radius r of the circle and the length of the diagonals of the rhombus.
  8. 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?
  9. 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.
  10. Radians
    pi_text Convert 54° to radians. Write result as multiple of number π.
  11. Expansion
    magnification If one side of the rectangle is larger 3-times and second 4-times, what percentage increases the area of rectangle?
  12. Maximum area of rhombus
    rhombus Calculate the interior angles at which equilateral rhombus has maximum area.
  13. 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 ?.
  14. 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?
  15. 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.
  16. Arc
    arc_1 Circle arc corresponding to angle is 193° is 23 dm long. What is the length of the entire circle?
  17. 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.
  18. Lathe
    soustruh From the cube of edge 52 cm was lathed maximum cylinder. What percentage of the cube is left as waste after lathed?
  19. Cube zoom
    krychle_1 How many percent we increase volume and surface of cube, if we magnify its edge by 61%.
  20. Kites
    drake Boys run kite on a cable of 86 meters long. What is the kite altitude, if the angle from the horizontal plane is 77°?

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