Circle - simple

Calculate the area of a circle in dm2, if its circumference is 31.4 cm.


S =  0.78 dm2


Solution in text S =

Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!

To solve this example are needed these knowledge from mathematics:

Next similar examples:

  1. Four circles
    circles_2 1) Calculate the circle radius if its area is 400 cm square 2) Calculate the radius of the circle whose circumference is 400 cm. 3) Calculate circle circumference if its area is 400 cm square 4) Calculate the circle's area if perimeter 400 cm.
  2. Math heart
    srdce_1 Stylized heart shape created from a square with side 5 cm and two semicircles over his sides. Calculate the content area and its circumference.
  3. Circle - easy 2
    circle_3 The circle has a radius 6 cm. Calculate:
  4. Cable
    wire Cable consists of 8 strands, each strand consists of 12 wires with diameter d = 0.5 mm. Calculate the cross-section of the cable.
  5. Pipe cross section
    pipe1 The pipe has an outside diameter 1100 mm and the pipe wall is 100 mm thick. Calculate the cross section of this pipe.
  6. Circle r,D
    bavlnka Calculate the diameter and radius of the circle if it has length 52.45 cm.
  7. Radius
    green_circle Determine the radius of the circle, if its perimeter and area is the same number.
  8. Lawns
    grass Before a sports hall are two equally large rectangular lawns, each measuring 40 m and 12 m. Maintenance of 10m² lawn cost 45 CZK yearly. On each lawn is circular flowerbed with a diameter 8 meters. How much money is needed each year to take on lawn care?.
  9. Sidewalk
    kruhovy-objazd The city park is a circular bed of flowers with a diameter of 8 meters, around it the whole length is 1 meter wide sidewalk . What is the sidewalk area?
  10. CD disc
    CD_disc A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters?
  11. Mine
    minetower Wheel in traction tower has a diameter 2 m. How many meters will perform an elevator cabin if wheel rotates in the same direction 66 times?
  12. Flowerbed
    garden_16 In the park there is a large circular flowerbed with a diameter of 12 m. Jakub circulated him ten times and the smaller Vojtoseven times. How many meters each went by and how many meters did Jakub run more than Vojta?
  13. Circle
    circle_1 What is the radius of the circle whose perimeter is 6 cm?
  14. Well
    well Rope with a bucket is fixed on the shaft with the wheel. The shaft has a diameter 50 cm. How many meters will drop bucket when the wheels turn 15 times?
  15. Wheel diameter
    koleso_1 A 1m diameter wheel rolled along a 100m long track. How many times did it turn?
  16. Rhombus 4
    diamond_shape Circumference of the rhombus is 44 cm, its height is 89 mm long. Calculate its content area.
  17. Right triangle ABC
    right_triangle_2 Calculate the perimeter and area of a right triangle ABC, if you know the length of legs 4 cm 5.5 cm and 6.8 cm is hypotenuse.