Examples for 8th grade - page 56

  1. Office
    hranol-6u Office building was built in the shape of a regular hexagon inscribed in a circle with a radius of 12 m. The height of the walls is 7m. How much CZK cost plastering the walls of the building, if per 1 m square cost CZK 400?
  2. ABS
    sphere_nice What is the value of ? ?
  3. Reservoir
    cylinder_Au 6 m long reservoir has a diameter of 2.2 m. What is its surface area in square meters?
  4. Parallelogram ABCD
    paralleogram_1 The area of parallelogram ABCD is 41 cm2. Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND?
  5. 6-gon
    hexagons Perimeter of regular hexagon is 41. Calculate its circumradius (radius of circumscribed circle).
  6. Alcohol 2
    alko Two types of alcohol one 70% and second 61% give 11 liters of 57% alcohol. How many liters of each type are in the mixture?
  7. Rhombus
    pqrs PQRS is a rhombus. Given that PQ=4 cm & height of rhombus is given 1.8 cm. Calculate its area.
  8. Tank 9
    water_cocks The tank with volume V is filled with one pump for three hours and by second pump for 5 hours. When both pumps will run simultaneously calculate: a) how much of the total volume of the tank is filled in one hour b) for how long is the tank full
  9. CD disc
    CD_disc A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters?
  10. Copy typist
    pisaci_stroj Typist for 12 hours rewritten 15% of the manuscript. After how many hours he will done 35% of the manuscript?
  11. Cube 9
    MD_cheese_cubes What was the original edge length of the cube if after cutting 39 small cubes with an edge length 2 dm left 200 dm3?
  12. Colour - billboard
    rovnobeznik_1 Shelftalker has the shape of a parallelogram. Its length is 4.9 m and the corresponding height is 3.5 meters. Calculate how much (kg) paint must purchase to redecoration if 1 kg cover 4 m2 of shelftalker surface.
  13. Seven tractors
    koleso Seven tractor plowed 308 ha field in four days. How many hectares of fields will plowe 9 tractors in 3 days at the same power?
  14. Bonbons 2
    bonbons_1 Kilo sweets will cost 260 CZK. The first type has a price per 320 kg, the second type 240 CZK per kg. How many kilos of both kinds of sweets need to prepare a 77 kg mixture ?
  15. Volume of three cuboids
    image10 Calculate the total volume of all cuboids for which the the size of the edges are in a ratio of 1:2:3, and one of the edges has a size 6 cm.
  16. Laths
    garaz There are two laths in the garage opposite one another: one 2 meters long and the other 3 meters long. They fall against each other and lean against the opposite walls of the garage both laths and touch at a height of 70 cm above the garage floor. How wide
  17. Holiday SMS
    sms Kucera and Malek start from the holiday together. They agreed that if they be 100 km apart, will send a SMS. Kucera traveling at 60 km/h., Malek 90 km/h. They started at 14 hours PM. At what time they send a message?
  18. Concentration
    ocet_1 How 0.5 liters of 8% vinegar diluted to a concentration of 20 hundredths % of vinegar? How many liters of water must be pour?
  19. Three friends
    three_friends Peter is eight times older than Rado, Rado is 3 times younger than Joseph. Together they have 120 years. Determine how many are each of them.
  20. Dusan
    parkets a) Dusan break two same window, which has triangular shape with a length of 0.8 m and corresponding height 9.5 dm. Find how many dm2 of glass he needs to buy for glazing of these windows. b) Since the money to fix Dusan has not, must go to the paint job

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