Examples for 8th grade - page 21

  1. Circles
    SquareCircleSquare Area of circle inscribed in a square is 14. What is the area of a circle circumscribed around a square?
  2. Right triangle
    thales_2 Draw a right triangle ABC if |AB| = 5 cm |BC| = 3 cm, |AC| = 4 cm. Draw Thales circle above the hypotenuse of the triangle ABC.
  3. Family and age ratios
    family_1 Age of father and son are in the ratio 10:3; age of father and daughter are in the ratio 5:2. How old is father and son, if daughter is 20 years old? In what ratio is age sister and brother?
  4. Tiles
    tiles_1 The room has dimensions 12 m and 5.6 m. Determine the number of square tiles and their largest possible size to cover them room's floor.
  5. Dog
    dog_and_man Man goes with a dog on a long walk 17 km from the house. Man is walking at speed 4.9 km/h and a dog that constantly running between house and man at 12.6 km/h. How many kilometers will run the dog when they reach their destination?
  6. Insurance
    tornado The owner of the house is insured against natural disasters and pays 0.04% annually of the value of house 77 Eur. Calculate the value of the house. Calculate the probability of disaster, if you know that 48% of the insurance is to pay damages.
  7. Isosceles III
    demos The base of the isosceles triangle is 17 cm area 416 cm2. Calculate the perimeter of this triangle.
  8. N-gon angles
    ngon2 What is the sum of interior angles 8-gon? What is the internal angle of a regular convex 8-polygon?
  9. Rectangle
    obdlznik_torta Area of rectangle is 3002. Its length is 41 larger than the width. What are the dimensions of the rectangle?
  10. Equilateral cylinder
    3d Equilateral cylinder (height = base diameter; h = 2r) has a volume of V = 199 cm3 . Calculate the surface area of the cylinder.
  11. Cuboid
    cuboid_3 Cuboid ABCDEFGH with 10 cm height has a base edge length 6 cm and 8 cm. Determine angle between body diagonal and the base plane (round to degrees).
  12. Bits, bytes
    bits Calculate how many different numbers can be encoded in 16-bit binary word?
  13. Children pool
    hexagon_prism2 The bottom of the children's pool is a regular hexagon with a = 60 cm side. The distance of opposing sides is 104 cm, the height of the pool is 45 cm. A) How many liters of water can fit into the pool? B) The pool is made of a double layer of plastic film.
  14. Tetrahedral prism
    hranol4sreg Calculate surface and volume tetrahedral prism, which has a rhomboid-shaped base, and its dimensions are: a = 12 cm, b = 7 cm, ha = 6 cm and prism height h = 10 cm.
  15. Degrees to radians
    angle Convert magnitude of the angle α = 9°39'15" to radians:
  16. Horizon
    lighthouse The top of a lighthouse is 19 m above the sea. How far away is an object which is just “on the horizon”? [Assume the earth is a sphere of radius 6378.1 km.]
  17. Quadrant II
    quartes_circle Calculate the radius of the quadrant, which area is equal to area of circle with radius r = 15 cm.
  18. Kids
    kids How many different ways can sit 8 boys and 3 girls in line, if girls want to sit on the edge?
  19. Cone in cylinder
    cone_in_cylinder The cylinder is inscribed cone. Determine the ratio of the volume of cone and cylinder. The ratio express as a decimal number and as percentage.
  20. Perpendicular
    slopeplane What is the slope of the perpendicular bisector of line segment AB if A[9,9] and B[9,-2]?

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