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Divide a circle into several equal parts, and make it into an approximate rectangle. It is known that the length of the rectangle is 6.28cm, and find the area of the circle cry for help.
Twice the length of a rectangle is the circumference of a circle, so the circumference of a circle is 12.56cm. The circumference of a circle is equal to pi * D, so the diameter d = 4cm
So the radius r = 2cm is 2 * 2 * 3.14 = 12.56cm ^ 2
Cut a circle into several equal parts along the radius, and then put it together into a rectangle. Given that the length of the rectangle is 4.28cm more than the width, what is the area of the circle?
Cut a circle into several equal parts along the radius, and then put it together into a rectangle. It is known that the length of the rectangle is 4.28cm more than the width, and what is the area of the circle? Several parts can be considered as innumerable parts. Then we can regard the arc as a straight line approximately. Let's assume that the radius of the circle is R. from the meaning of the title, we know that the width of the rectangle is also R, and the circumference of the circle is a rectangle
Divide a circle into several equal parts to form an approximate rectangle. The circumference is 5cm more than the original. What is the area of the circle?
Let the diameter of the circle be x cm
3.14x + 5 = 3.14x + X
x=5
5/2*5/2*3.14=19.625cm*cm
Divide a circle into several equal parts, and then form an approximate rectangle. The width of the rectangle is 8.56 cm less than the length. What is the area of the original circle?
The first one who told me the correct answer scored 20!
The sum of width is diameter, and the sum of length is circumference, so the diameter is 8.56 △ 3.14-1 = 4cm
Area of circle:
3.14 × (4 △ 2) &# 178; = 12.56 square centimeter
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