If the surface area of a cone is 9 and its side view is a semicircle, the diameter of the bottom of the cone can be calculated

Let the bus length a, the circumference of the bottom surface be 1 / 2 * 2, and a = a, that is, the radius of the bottom surface is a / 2, the area of the bottom surface is a / 4, the area of the side surface is a / 2, and 9 = 3 / 4. The solution is that a = root sign (12 / no) is equal to the diameter of the bottom surface, and the root sign (3 / no) is reduced to 2

When a circle is enlarged, its area is eight times larger and its circumference is 50.24 cm longer than before. What is the original area?

The area of the circle has been expanded eight times, that is, it has been expanded nine times and its circumference has been expanded three times. Therefore, the original circumference of the circle is
50.24 cm △ 2 = 25.12 cm
So, the original radius of this circle is
25.12÷3.14÷2=4
What is the original area of this circle
4 × 4 × 3.14 = 50.24 square centimeter

When a circle is enlarged, its area is eight times larger and its circumference is 50.24 cm larger than the original. The original area of the circle is______ Square centimeter

50.24 △ 3.14 △ 2 = 8 (CM); 8 + 1 = 9, 9 = 3 × 3, 3-1 = 2, 8 △ 2 = 4 (CM); 3.14 × 42, = 3.14 × 16, = 50.24 (CM); answer: the original area of this circle is 50.24 square cm, so the answer is 50.24

When a circle is enlarged, its area is eight times larger and its circumference is 50.24 cm larger than the original. The original area of the circle is______ Square centimeter

When the radius of a circle is enlarged, its area is eight times larger and its circumference is 75.36 cm larger than the original, then the area of the circle is

When the radius of a circle is enlarged, its area is eight times larger and its circumference is 75.36 cm larger than the original, then the area of the circle is
If the area is increased by (1 + 8) = 9 times, the perimeter is increased by 3 times
Radius 75.36 △ 3.14 △ 2 = 6cm
Area: 3.14 × 6 × 6 = 113.04 square centimeter

Why is the area of a circle the largest when its perimeter is equal?

Firstly, it is proved that the area of regular polygon is the largest when the number of sides is equal. For example, if two adjacent sides are not equal, it is easy to prove that the area of regular polygon is larger than the original area when they are changed to be equal once the length and sum are kept unchanged, so the largest area is regular polygon

Why is the area of a circle the largest when the circumference is equal?

Think about the area of a circle?
Divide a circle into N equal parts and arrange it into a rectangle. The area of the circle is equal to half of the circumference multiplied by the radius! The circumference of the rectangle is equal to 2 radii longer than the circumference of the rectangle!

Two circles have the same area and the same perimeter______ (judge right or wrong)

Because the PI is fixed, the area of two circles is equal, the radius of two circles must be equal, so their perimeter must be equal

The area of a rectangle and a square is 324cm2, and that of a circle is 314cm2. Among the three figures, () has the largest perimeter and () has the smallest perimeter. If the three figures have the same area, can you find the size relationship between their girths?

The area of a rectangle and a square is 324cm2, and that of a circle is 314cm2. Among the three figures, the perimeter of (rectangle) is the largest, and that of (circle) is the smallest

As shown in the figure, the area of the circle is 25.12 square centimeters, and the area of the shadow part is______ Square centimeter

Because the area of the circle = π R2, R2 = 25.12 △ 3.14 = 8 (square centimeter); answer: the area of the shadow is 8 square centimeter; so the answer is: 8

If the surface area of a cone is 9 and its side view is a semicircle, the diameter of the bottom of the cone can be calculated