Perimeter - 7th grade (12y) - math problems

  1. Central angle
    obluk What is the length of the arc of a circle with a diameter of 46 cm, which belongs to a central angle of 30°?
  2. Length of the arc
    obluk What is the length of the arc of a circle k (S, r=68mm), which belongs to a central angle of 78°?
  3. The hollow cylinder
    duty_valec The hollow cylinder has a height of 70 cm, an outer diameter of 180 cm and an inner diameter of 120 cm. What is the surface of the body, including the area inside the cavity?
  4. What is bigger?
    ball_f Which ball has a larger volume: a football with a circumference of 66 cm or a volleyball with a diameter of 20 cm?
  5. Winch drum
    bubon Originally an empty winch drum with a diameter of 20 cm and a width of 30 cm on the rescue car, he started winding a rope with a thickness of 1 cm beautifully from edge to edge. The winch stopped after 80 turns. It remains to spin 3.54m of rope (without h
  6. The Earth
    earth The Earth's surface is 510,000,000 km2. Calculates the radius, equator length, and volume of the Earth, assuming the Earth has the shape of a sphere.
  7. Perimeters
    triangles A rectangle has a perimeter of 16p centimeters, it had a width of 2p centimeters. Each side of an equilateral triangle is 1/2 the length of the rectangle. Find the total perimeter of the rectangle and the triangle if p=8.
  8. Sum of the edges
    cube_shield The sum of the lengths of all edges of the cube is 72 cm. How many cm2 of colored paper are we going to use for sticking?
  9. Cross five
    5squares2 The figure on the picture is composed of the same squares and has a content of 45cm². What's its perimeter?
  10. Plot
    plot The land is in the shape of a square with a dimension of 22 meters. How much will we pay for the fence around the entire plot?
  11. Perimeter of the circle
    squares Calculate the perimeter of the circle in dm, whose radius equals the side of the square containing 0.49 dm2?
  12. Tablecloths
    obrus The restaurant has sixty-two square tablecloths with a side length of 150 cm and 36 rectangular tablecloths with dimensions of 140 cm and 160 cm. A) How many meters of hemming ribbon will be needed if we add 50 cm to each tablecloth? B) The ribbon sale
  13. Rectangles
    rectangles_1 Vladimir likes to draw rectangles. Yesterday he created all rectangles that had sides in centimeters and a circumference of 18 cm. How many rectangles of different dimensions have been drawn?
  14. Coal mine
    koleso The towing wheel has a diameter of 1.7 meters. How many meters does the elevator cage lower when the wheel turns 32 times?
  15. Radius of the circle
    circle_axes Calculate the radius of the circle whose length is 107 cm larger than its diameter
  16. Let x
    rectangle Let x represent one quantity. State what that quantity represents. Express the second quantity in terms of x. The length of the rectangle is 4 inches less than 8 times the width.
  17. The perimeter 3
    rectangles The perimeter of a rectangle is 35 cm. The ratio of the length to its width is 3:2. Calculate the dimensions of the rectangle
  18. Triangular prism
    prism_rt Calculate a triangular prism if it has a rectangular triangle base with a = 4cm and hypotenuse c = 50mm and height of the prism is 0.12 dm.
  19. Velocipedes
    Velocipede In the 19th century, bicycles did not have a chain drive, and the pedals were connected directly to the wheel axis. This wheel diameter gradually increased until the so-called high bicycles (velocipedes) with a front wheel diameter of up to 1.5 meters, wh
  20. Ribbon on the cube
    gift A cubical gift box is tied with a piece of ribbon. If the total length of the free ends and the bow is 18 inches, what is the length of the ribbon used? (Each side of the cube is 6 inches).

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