Examples for 8th grade - page 8

  1. Circumscribing
    thales Determine the radius of the circumscribed circle to the right triangle with legs 3 cm and 3 cm.
  2. Tetrahedral pyramid
    jehlanctyrboky What is the surface of a regular tetrahedral (four-sided) pyramid if the base edge a=23 and height v=8?
  3. Lorry
    lorry The lorry was loaded with 27 boxes of 24 kg. How many boxes with weight 36 kg can be loaded, if total load must be same?
  4. Clock
    hodiny How many times a day hands on a clock overlap?
  5. Phone numbers
    old_phone How many 9-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated?
  6. Climb in percentage
    12_percent_stupanie The height difference between points A and B is 442 m. Calculate the percentage of route climbing if the horizontal distance places A, B is 6.8 km.
  7. New refrigerator
    lednice New refrigerator sells for 878 USD, Monday will be 25% discount. How much USD will save, and what will be the price?
  8. Friends in cinema
    cinema_1 5 friends went to the cinema. How many possible ways can sit in a row, if one of them wants to sit in the middle and the remaining's place does not matter?
  9. Car inflation
    car_1 About what percentage price of car increased if price rose from €5000 to €5130?
  10. Similarity of squares
    squares2_1 The ratio of the similarity of the squares ABCD and KLMN is 2.5. Square KLMN area is greater than area of a square ABCD with side a: ?
  11. Pentagon
    5gon_1 Within a regular pentagon ABCDE point P is such that the triangle is equilateral ABP. How big is the angle BCP? Make a sketch.
  12. Estate
    semicircle Semicircle estate must be fence. The straight section has 44 meters long fence. How many meters of fence should buy?
  13. Trapezoid MO-5-Z8
    lichobeznik_mo_z8 ABCD is a trapezoid that lime segment CE divided into a triangle and parallelogram as shown. Point F is the midpoint of CE, DF line passes through the center of the segment BE and the area of the triangle CDE is 3 cm2. Determine the area of the trapezoid A
  14. Square grid
    sit Square grid consists of a square with sides of length 1 cm. Draw in it at least three different patterns such that each had a content of 6 cm2 and circumference 12 cm and that their sides is in square grid.
  15. Division
    bonbons Three siblings Helena, Oliver and George split the bag with candies on merit in the ratio 1:6:3. How many candies should each get if in bag were 210?
  16. Lie/do not lie
    lines_and_points The function is given by the rule f(x) = -x-12. Determine whether point D[-4; 2] lies on this function. Solve graphically or numerically and give reasons for the your answer.
  17. Sphere growth
    sphere How many times grow volume of sphere if radius rises 3×?
  18. Intersections
    intersect_circles How many intersections have circles with radius 12 dm and 17 dm, if the distance of their centers is 20 dm.
  19. Reciprocal
    inverse It is true (prove it) that if a> b> 0: ?
  20. Air mass
    airbaloon What is the weight of the air in a classroom with dimensions 5 m × 2 m × 3.1 m ? The air density is 1.293 kg/m3.

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