Examples for 8th grade - page 21

  1. Concrete pipe
    concrete_pipe Concrete pipe is cylindrical with an inner diameter 130 cm and outer 142 cm. Calculate the surface of the concrete pipe, if it is 6 m long.
  2. Height
    equilateral_triangle Calculate height of the equilateral triangle if its perimeter is 54?
  3. Task
    cube_1 I have homework. The cube has an edge 11 cm long and I must find wall and body diagonal.
  4. Triangular prism
    hranol_3 Base of perpendicular triangular prism is a right triangle with leg length 5 cm. Content area of the largest side wall of its surface is 130 cm² and the height of the body is 10 cm. Calculate its volume.
  5. ISO trapezium
    trapezium_2 Calculate area of isosceles trapezoid with base 53 long, leg 43 long and with the angle between the base and leg 70 degrees.
  6. Circumferential angle
    uhly Vertices of the triangle ΔABC lies on circle and divided it into arcs in the ratio 5:5:3. Determine the size of the angles of the triangle ΔABC.
  7. Distance
    distance Calculate distance between two points Z[7; -9] and U[-10; -8].
  8. Cuboid
    kvadr Find the cuboid that has the same surface area as the volume.
  9. Icerink
    klzisko-korcule Rectangular rink with dimensions of 79.5 m and 529 dm must be covered with a layer of ice 4.5 cm thick. How many liters of water is necessary for the formation of ice when the volume of ice is 10.9% greater than the volume of water.
  10. Two workers
    Frog Two workers together execute some work in 10 days. The first worker would have done himself in 20 days. How many days would have done himself a second worker?
  11. Tank
    barrel_1 In the middle of a cylindrical tank with a bottom diameter 350 cm is standing rod which is 31 cm above the water surface. If we bank rod its end reach surface of the water just by the tank wall. How deep is the tank?
  12. Pizza
    pizza_1 A school survey found that 9 out of 16 students like pizza. If 5 students are chosen at random, what is the probability that all 5 students like pizza?
  13. Map - climb
    Lanovka_na_skalnate_pleso On the map of High Tatras in scale 1:25000 are cable car stations in the Tatranska Lomnica and in the Skalnate Pleso with distance 156 mm. Altitude of this stations are 944 m and 1755 m. What is average angle of climb of this cable car track?
  14. Trains for people
    757_rusen It is said that the train is synonymous to delay. Calculate the average speed of travel by train long 50 km, with regular train leave at 6:05 and arrive at 7:20, but train is late and has departure at 9:52 and arrive at 11:05.
  15. Purchase
    cart Mother bought 5 boxes of milk and 7 kg of potatoes and paid a total CZK 147. Aunt bought 7 boxes of milk and 3 kg of potatoes and paid 131 CZK. What is the price of one carton of milk and 1 kg of potatoes? How CZK together would have saved if bought at the
  16. Salary
    500euro Clerk got to pay 1200 Euros in banknotes of 50 and 200 Eur. Total got 9 banknotes. How many was which?
  17. Lunch for free
    Gastrolistky Gastro ticket are "free" and therefore they should be retained. This think many employees in Slovakia. Calculate how much money employee yearly earn if he get 217 gastro tickets of 2.7 € and you know that the company issuing gastro tickets get 4.4% fee of
  18. Kids
    kids How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
  19. Salary
    platy Calculate equivalent annual salary to hourly salary $ 29. Assume a 40-hour work week.
  20. Column
    pole_phone Perpendicular pole high 6 m tall broke and its toe fell 2.8 m from the bottom of the pole. At what height above the ground pole broke?

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.

To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.