Expression of a variable from formula - examples

  1. Rectangle 35
    rectangles_13 Find the area of a rectangle when the diagonal is equal to 30 cms and the width is double the length.
  2. Hollow sphere
    sphere2 The volume of the hollow ball is 3432 cm3. What is its internal radius when the wall thickness is 3 cm?
  3. Circle and rectangle
    described_circle A rectangle with sides of 11.7 cm and 175 mm is described by circle. What is its length? Calculate the content area of the circle described by this circle.
  4. Square pyramid
    pyramid_4 Calculate the volume of the pyramid with the side 5cm long and with a square base, side-base has angle of 60 degrees.
  5. Pagans
    circles2_3 Elena cut out same circle-shaped pagans and put them on a rectangular sheet so that the neighboring pagans were touching each other and the pagans were touching the walls of the sheet on the edges. Each pagans occupied 28.26 cm2 of the bottom of the sheet.
  6. Diameter
    circles2_1 What is the inside diameter of the cylinder container and if half a liter of water reaches a height 15 cm?
  7. Angle of deviation
    kuzel2_1 The surface of the rotating cone is 30 cm2 (with circle base), its surface area is 20 cm2. Calculate the deviation of the side of this cone from the plane of the base.
  8. Nice prism
    diagonal_rectangular_prism.JPG Calculate the surface of the cuboid if the sum of its edges is a + b + c = 19 cm and the body diagonal size u = 13 cm.
  9. Quadrangular prism
    trapezium_prism The quadrangular prism has a volume 648 cm3. Trapezoid which is its base has the dimensions bases: a = 10 cm, c = 5 and height v = 6 cm. What is the height of the prism?
  10. Plot
    rectangle_5 The length of the rectangle is 8 smaller than three times the width. If we increase the width by 5% of the length and the length is reduced by 14% of the width, the circumference of rectangle will be increased by 30 m. What are the dimensions of the rectan
  11. Euros
    eura_8 Peter spent a quarter of his pocket saving. He has 9 euros now in his wallet . How many euros spent?
  12. Disc
    vysek.JPG Circumference of the disk is 78.5 cm. What is the circumference of the circular arc of 32° on the disc?
  13. Trucks
    bricks Three lorries droved bricks. One drove n bricks at once, second m less bricks than the first and third 300 bricks more the first lorry. The first lorry went 4 times a day the largest went 3 times a day and the smallest 5 times a day. How many bricks br
  14. Trapezoid
    lichob_2_1 How long are the trapezoid bases with area 24 cm2 and height 3 cm. One base is 3 times longer than the shorter.
  15. Cylinder - h
    cylinder_2 Cylinder volume is 129 cm3. Base radius is 3 cm. Calculate the height of the cylinder.
  16. MO SK/CZ Z9–I–3
    ball_floating_water John had the ball that rolled into the pool and it swam in the water. Its highest point was 2 cm above the surface. Diameter of circle that marked the water level on the surface of the ball was 8 cm. Determine the diameter of John ball.
  17. Theater
    SND The theater has in each row with 11 seats. Ticket to the first 8 rows is for 198 KČ. In next rows is for 84 KČ. The theater was completely sold out. Revenue was 34980 KČ. How many rows are in the theater?
  18. Garden
    garden_2 Father dig up the garden in 13 hours. Son in 18 hours. How many hours take dig up the garden together?
  19. 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: ?
  20. Painters
    natieraci Five painters painting the fence for eight days. How many days over will take work if paint the fence only four decorators?

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