Expression of a variable from formula - examples

  1. Cuboid and eq2
    kvader11_2 Calculate the volume of cuboid with square base and height 6 cm if the surface area is 48 cm2.
  2. Average speed
    bus27_4 When the bus stops at bus stops driving average speed is 45 km/h. If it did not stop it drive at speed 54 km/h. How many minutes of every hour it spend at stops?
  3. Diagonals of a rhombus
    rhombus-diagonals_1 One of the diagonals of a rhombus is twice as the other. If the sum of the lengths of the diagonals is 24, find the area of the rhombus.
  4. Right triangle eq2
    rt_2 Hypotenuse of a right triangle is 9 cm longer than one leg and 8 cm longer than the second leg. Determine the circumference and area of a triangle.
  5. Cube and sphere
    gule_1 Cube with the surface area 150 cm2 is described sphere. What is sphere surface?
  6. Rhombus and diagonals
    kosostvorec_2 The a rhombus area is 150 cm2 and the ratio of the diagonals is 3:4. Calculate the length of its height.
  7. Cylinder - h
    cylinder_2 Cylinder volume is 242 cm3. Base radius is 1 cm. Calculate the height of the cylinder.
  8. 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.
  9. 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?
  10. Garden
    garden_2 Father dig up the garden in 13 hours. Son in 18 hours. How many hours take dig up the garden together?
  11. 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: ?
  12. Triangles
    green_triangle Equilateral triangle with side 25 cm has the same perimeter as an isosceles triangle with arm of 32 cm. Calculate the base x of an isosceles triangle.
  13. 7 triangle
    coloured_triangle The triangle area is 71.4 cm2. Determine the side length j if appropriate height hj = 39.3 cm.
  14. Expressions
    equation Expression (3a-7).(3a+7) is identical with: ?
  15. MO-Z5-3-66 tiles
    stvorce The picture shows a square tiles with side 10 dm which is composed of four identical small rectangles and squares. Circumference of small square is five times smaller than the circumference of the entire tile. Determine the dimensions of the rectangle.
  16. Harvesters
    kombajny The first harvester reaps the grain from land for 24 hours, the second harvester for 16 hours. For how many hours will take harvest by two harvesters, but the second harvester started working four hours later than the first?
  17. Circle
    circle How big is area of circle if its circumference is 58.7 cm?
  18. Cleaners
    clean Milan would clean up the room for 2.5 hours, Eric would take 10 hours. How long they swept the room together?
  19. One and a half chicken
    chicken_1 One and a half chicken bears one and a half egg in one and a half day. How many eggs can withstand from 21 chicken in 21 days?
  20. Floor
    podlaha Rectangular floor of living room has a length 5.4 meters and a circumference 17.2 meters. What is its width?

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