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Cut out the largest circle in a rectangle 6cm long and 4cm wide. The circumference of the circle is______ The area is______ There is still an area left______ ．
The circumference of the circle is 3.14 × 4 = 12.56 (CM), the area is 3.14 × (4 △ 2) 2 = 12.56 (CM), and the remaining area is 6 × 4-12.56, = 24-12.56, = 11.44 (CM). A: the circumference of the circle is 12.56 cm, the area is 12.56 cm, and the remaining area is 11.44 cm
Draw the largest circle in a rectangle 6cm long and 4cm wide. The circumference of the circle is () and the area is ()
r=2
s=12.56
l=12.56
The diameter of the small circle is 4cm, the radius of the big circle is 4cm, the ratio of the circumference of the big circle to that of the small circle is (), and the area ratio is ()
The diameter of the small circle is 4cm, the radius of the big circle is 4cm, and the ratio of the circumference of the big circle to that of the small circle is (2:1),
The area ratio is (4:1)
Idea: first find out the radius of small circle: 4 / 2 = 2cm, and then find out the radius ratio of big circle and small circle is 4:2, that is 2:1
Then using radius ratio = diameter ratio = perimeter ratio and area ratio as their square ratio, it is concluded that the ratio of large and small circumference length is 2:1 and area ratio is 4:1
The radius of a circle is 4cm. What is the circumference of a semicircle?
This problem Xiaohua does as follows: 1. Find the circumference of a circle: 3.14 × 2 × 4 = 25.12 (CM); 2. Find the circumference of a semicircle: 25.12 △ 2 = 12.56 (CM)
Do you think Xiaohua is doing it right? If not, please explain it in words, pictures or ways you like, and then write down the correct way
No, it is: 3.14 × (4 × 2) = 25.12 (CM) 25.12 △ 2 = 12.56 (CM) 12.56 + 4 × 2 = 20.56 (CM)
The radius of a circle is five centimeters. What is the circumference and area of the circle
L=2πr=10π
S=πr^2=25π
1. The radius of a circle is expanded to 5 times of the original, the circumference of the circle is expanded to () times of the original, and the area is expanded to () times of the original
2. The radius of the big circle is equal to the diameter of the small circle, and the area ratio of the big circle to the small circle is ()
3. Draw the largest circle in a square whose side length is 6cm, and the area of the circle accounts for () of the square
4. The base and height of the triangle are expanded to 5 times of the original, and its area is expanded to ()
5. A rectangle is 8m long and 6m wide. If its length and width are increased by 2m, its area will be increased ()
1. The radius of a circle is expanded to 5 times of the original, the circumference of the circle is expanded to (5) times of the original, and the area is expanded to (25) times of the original
2. The radius of the big circle is equal to the diameter of the small circle, and the area ratio of the big circle to the small circle is (4:1)
3. Draw the largest circle in a square whose side length is 6cm, and the area of the circle accounts for 78.5% of the square
4. The base and height of the triangle are expanded to 5 times of the original, and its area is expanded to (25)
5. A rectangle is 8m in length and 6m in width. If its length and width are increased by 2m, its area will be increased (32 square meters)
If the radius of a circle increases by 5%, the area of the circle increases by ()%
(1.05^2-1)*100%=10.25%
How many times does the radius of a circle increase by five times and the area of that circle increase?
Is to increase a few times, not to expand a few times ~ please help my friends
Answer: 24 times
The area increased 25 times, increased 25-1 = 24 times
CCTV "Happy Dictionary" column once had such a question: if the radius of the circle doubled, then the area of the circle increased ()
A. Double B. double C. triple D. quadruple
Let R be the original radius of the circle, which is doubled, and 2R be the radius, then the increased area is 4 π R2 - π R2 = 3 π R2, which is increased by three times
If you increase the radius of a circle to three times the original, the area of the circle will be reduced
If you increase the radius of a circle by three times, the area of the circle will increase by nine times
RELATED INFORMATIONS
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- 2. The radius of a circle is 2 cm. How many square meters is the area of the circle
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- 12. A ring with an inner diameter of 5cm and an outer radius of 3cm. The area of the ring is______ cm2．
- 13. The outer diameter of a ring is 1.5cm, and the inner diameter is 1cm. What is the area of the ring?
- 14. The outer radius and inner diameter of a ring are 5cm, and the area of the ring is () square cm?
- 15. There are three small circles in the diameter of the big circle. The diameter of the big circle is 5cm, and the diameter of the small circle is 2.5 cm, 1.5 cm and 1cm respectively. The sum of the circumference of the big circle and the three small circles is compared After comparison, which is longer? Which is shorter?
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