Examples for 8th grade - page 21

  1. Tank
    barrel_1 In the middle of a cylindrical tank with a bottom diameter 251 cm is standing rod which is 13 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?
  2. Inscribed rectangle
    circle_desc_rectangular The circle area is 216. Determine the area of inscribed rectangle with one side 5 long.
  3. Map
    mapa_bce Forest has an area of ​​36 ha. How much area is occupied by forest on the map at scale 1:500?
  4. Distance
    distance Calculate distance between two points X[18; 19] and W[20; 3].
  5. Root
    sq_root Use law of square roots roots: ?
  6. 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.
  7. Cathethus and the inscribed circle
    RightTriangleInradius In a right triangle is given one cathethus long 14 cm and the radius of the inscribed circle of 5 cm. Calculate the area of this right triangle.
  8. Shots
    broky 5500 lead shots with diameter 4 mm is decanted into a ball. What is it diameter?
  9. Triangular prism
    hranol_3bokovy Calculate the surface area and volume of a triangular prism, base right triangle if a = 3 cm, b = 4 cm, c = 5 cm and height of prism h=12 cm.
  10. Sales vs profit
    Acer+vs+Apple Apple sells 22 percent less computes than the Acer but the profit from their sales is 2.2 times higher than Acer. How many times are Apple computer more expensive than Acer?
  11. 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
  12. Rectangle diagonals
    rectangle_diagonals_1 It is given rectangle with area 24 cm2 a circumference 20 cm. The length of one side is 2 cm larger than length of second side. Calculate the length of the diagonal. Length and width are yet expressed in natural numbers.
  13. Euler problem
    euler Someone buys a 180 tolars towels. If it was for the same money of 3 more towels, it would be 3 tolars cheaper each. How many were towels?
  14. Felix
    astronaut Calculate how much land saw Felix Baumgartner after jump from 32 km above ground. The radius of the Earth is R = 6378 km.
  15. Count of roots
    eggs How many solutions has equation x. y = 7757 with two unknowns on the set of natural numbers?
  16. Sphere growth
    sphere How many times grow volume of sphere if diameter rises 10×?
  17. Intersections
    intersect_circles How many intersections have circles with radius 16 mm and 15 mm, if the distance of their centers is 16 mm.
  18. Water container
    water_1 Container with water weighs 1.48 kg. When we cast 75% of water container of water weight 0.73 kg. How heavy is an empty container?
  19. Circumferential angle
    uhly Vertices of the triangle ΔABC lies on circle and divided it into arcs in the ratio 5:3:10. Determine the size of the angles of the triangle ΔABC.
  20. 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?

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