# Circle - 7th grade (12y) - math problems

#### Number of problems found: 190

- Tractor wheels

The front wheel of the tractor has a circumference of 18 dm and the rear 60 dm. We will make a red mark on the lowest point of both wheels. The tractor then starts. At what distance from the start will both marks appear identically at the bottom again? - Gears

The front gear on the bike has 32 teeth and the rear, on the wheel, has 12 teeth. How many times does the bike's rear-wheel turn if you turn the right pedal 30 times? What distance will you go if the circumference of the bicycle wheel is 250 cm? - On a

On a some day, the Sun, Venus and the Earth are in eclipse, i. E. Venus is between the Sun and the Earth. Venus orbits the Sun in 225 days. In how many years will all three bodies be in alignment again? - Length of the arc

What is the length of the arc of a circle k (S, r=68mm), which belongs to a central angle of 78°? - The hollow cylinder

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? - Coordinates hexagon

The regular hexagon ABCDEF is given. Point A has coordinates [1; 3], and point D has coordinates [4; 7]. Calculate the sum of the coordinates of the center of its described circle. - Winch drum

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 - Tunnel boring

How much material did they dig when cutting the 400m long tunnel? The content of the circular segment, which is the cross section of the tunnel is 62m^{2}. - Outside tangents

Calculate the length of the line segment S_{1}S_{2}if the circles k_{1}(S_{1}, 8cm) and k2 (S_{2},4cm) touch the outside. - The length

The length of the circle is 24 cm. What is the length of the circular arc of the corresponding angle 30°? - Perimeter of the circle

Calculate the perimeter of the circle in dm, whose radius equals the side of the square containing 0.49 dm^{2}? - Radius

Find the radius of the circle with area S = 200 cm². - Coal mine

The towing wheel has a diameter of 1.7 meters. How many meters does the elevator cage lower when the wheel turns 32 times? - Radius of the circle

Calculate the radius of the circle whose length is 107 cm larger than its diameter - RPM

An electric motor makes 3,000 revolutions per minutes. How many degrees does it rotate in one second? - Steel tube

The steel tube has an inner diameter of 4 cm and an outer diameter of 4.8 cm. The density of the steel is 7800 kg/m^{3}. Calculate its length if it weighs 15 kg. - Ratio of volumes

If the heights of two cylindrical drums are in the ratio 7:8 and their base radii are in the ratio 4:3. What is the ratio of their volumes? - Metal tube

Calculate the metal tube mass 8dm long with the outer radius 5cm and the inner radius 4.5cm and 1cm^{3}of this metal is 9.5g. - Cube into cylinder

If we dip a wooden cube into a barrel with a 40cm radius, the water will rise 10 cm. What is the size of the cube edge? - The pot

The pot is a cylinder with a volume of V = 7l and an inner diameter of d = 20cm. Find its depth.

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Circle Problems. Examples for 7th grade (seventh).