(1).① The cross-sectional diameter of cylindrical steel is 60 cm. What is the perimeter and area of the cross section?
○2 The cross-sectional area of a log is 0. 176625 square meters, so what is the circumference of the cross-section?
○3 Two iron wires with a length of 12 and 56 decimeters are used to form a square and a circle respectively, which figure has a larger area?
○4 The diameter of a semicircle is 20cm, so what is the circumference and area of this semicircle?
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(2) 1 In a circular flower bed with a diameter of12m, the outer diameter of a car wheel is1.5m.. If this car
Color floor tiles with a width of 2 meters are laid around, and the wheels rotate 250 times per minute when driving. Then, every car,
What is the floor tile area? How many kilometers per hour? (Keep integer)
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(3).○ 1 ring with an outer diameter of 25cm and an inner diameter of 15cm. How many square centimeters is the area of this circle?
○2 Cut a square colored paper with a side length of 32cm into a circle as large as possible. What is the area of this circle?
○3 Cut a circular piece of paper with a diameter of 4dm into a square as large as possible. What is the area of a square?
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(4). 1 The outer diameter of the front wheel of the bicycle is 0.502, which surrounds a circular lawn with a diameter of 20 meters.
The outer diameter of the rear wheel is 0.8m.. At present, one flower is planted in 20cm rotation. * * * How many flowers have you planted? This lawn
How many times did you turn around on lap 40? How many square meters is the area?
○3 The sum of the perimeters of two circles is 56.52cm. How many times is the circumference of a half circle?
The radius of a circle is five times that of a small circle. Then, the radius of the big circle and the small circle is doubled, and the circumference of the circle is expanded by how many times?
How many square centimeters is the area? How many times has the area expanded?
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(5).○ The figure is 1, and the figure is square ABCD ○2, which is called semicircle.
The area of is 12 1 cm2, and the top circumference is 25.7cm. Find the shadow.
Points A, B, C and D are the perimeters and areas of the four circular parts, respectively.
Center of the circle What is the total area?
Square centimeters?
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(6).○ 1 As shown in the figure, from place A to place B as shown in Figure 2, part of it
There are two feasible methods, one is arc scheme. Find this graphic.
Line ○ 1, and the other line takes arc ○2. The circumference and area of please is.
Which road is shorter? Why? How much/how much?
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(7). 1 As shown in the figure, the area of a square is .02 as shown in the figure, and the area of a circle is 6.28 flat.
It's 20 square centimeters. Find the area of a circle. Square decimeter and rectangular surface.
Twice as many products. Find the shadow area.
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(8).○ 1 As shown, it is a playground. As shown in the figure, the radius of the circle is
Plan, find 70 10 cm of this plan, and find the shaded part.
What are the perimeter and area respectively? What is the total area?
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(9).○ 1 as shown in the figure. ○ 2 of a square is called a square.
Side length 10 cm, shadow side length 8 cm, so
What is the area of the part? What is the area of the shaded part?
Centimeter? How many square centimeters is the total?