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Cone, sphere, frustum, cylinder, which of these four kinds of geometry is equal to the plane figure seen from above
Looking down from above, the plane figure of each object is: cone (a circle with a point in the middle), ball (a circle), frustum (two concentric circles), cylinder (a circle), then the same is the ball and cylinder!
The cone is surrounded by () faces, and the plane figure is ()
emergency
A cone is surrounded by (2) surfaces, and the plane figure obtained by expanding the side of the cone is (fan-shaped)
Let Ω be the outside of the cylinder x ^ 2 + y ^ 2 = a ^ 2 between z = 0 and z = 1, then FF (x ^ 2 + y ^ 2) DXDY
For double integral, the projection plane is actually on xoy, but the projection of the cylindrical surface on xoy is only a circle (excluding the interior), and the estimated area is zero
What does plane x + y + Z = 0 look like?
For example, is it a circle with radius a cut by the surface x ^ 2 + y ^ 2 + Z ^ 2 = a ^ 2? Why?
In this plane, you can imagine the cube abcd-a'b'c'd ', which is placed on the side. We face the diagonal plane of acc'a', the midpoint of Ba and BC, the midpoint of AA ', CC', the midpoint of d'a ', and the midpoint of d'c'. The section formed by these six midpoint is the image of X + y + Z = 0 with the center of the square as the origin
High number, find the linear equation passing through point m (1, - 2,3) and parallel to two planes 2x + 3Y + Z-1 = 0 and X + y-3z + 2 = 0
The volume of a cone with a base radius of 6 cm is equal to that of a cylinder of equal height with a base radius of 2 cm
The volume of a cylinder with a base radius of 2 cm: v = π 2 & sup2; H = 4 π H
The volume of a cone with a base radius of 6 cm: v = 1 / 3 π 6 & sup2; H = 12 π H
So it's not right
The height of the two cylinders is equal, the ground radius of the large cylinder is equal to the bottom diameter of the small cylinder, and the volume of the small cylinder is?%
The radius ratio is 2:1
The volume ratio is 2 × 2:1 × 1 = 4:1
The volume of a small cylinder is 1 △ 4 = 25% of that of a large cylinder
The diameter of the bottom circle of the small cylinder is 8 cm, and the height is 6 cm. The diameter of the bottom circle of the large cylinder is 10 cm, and its volume is 2.5 times that of the small cylinder
It is required to set up a linear equation of one variable, and the height of the large cylinder is x cm
Know from the title
The volume of a large cylinder is
Square of Wu (10 / 2) = 2.5 x 6 Wu (8 / 2)
The equation of one variable is reduced to 25X = 2.5x6x16
The solution of the equation is x = 9.6
A cylinder, whose height is three times the radius of the bottom, is divided into two cylinders, the large and the small. If the surface area of the large cylinder and the surface area of the small cylinder is 3:1, then
How many times the volume of a large cylinder is that of a small one
Suppose the radius is 1 and the height is 3
3.14 * 1 * 1 = 3.14 (bottom area)
2 * 3.14 * 1 = 6.28 (bottom perimeter)
6.28 * 3 = 18.84 (side area)
18.84 + 3.14 * 4 = 31.4 (total area after incision)
31.4 / (3 + 1) = 7.85 (surface area of small cylinder)
31.4-7.85 = 23.55 (surface area of large cylinder)
7.85-3.14 * 2 = 1.57 (side area of small cylinder)
23.55-3.14 * 2 = 17.27 (side area of large cylinder)
17.27 / 1.57 = 11 times (the big cylinder is several times of the small cylinder)
Because when the bottom area is fixed, the volume of the cylinder is proportional to the height, because the multiple of the height is equivalent to the multiple of the volume
Both the surface area and the diameter of the bottom of the cylinder already know how to find the height
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[thinking of doing questions]
In this problem, the known conditions are very sufficient, can make the result completely
1. According to the diameter of the bottom surface, the radius and perimeter of the bottom surface are obtained: radius = diameter △ 2, perimeter = diameter × π
2. Using the radius of the bottom surface to calculate a bottom surface area: radius × radius × π
3. Using the diameter of the bottom surface to calculate the perimeter of the bottom surface: diameter × π
4. Calculate the side area of the cylinder by the surface area of the cylinder: the surface area of the cylinder - 2 × the bottom area
5. The height of the cylinder is calculated from the side area of the cylinder
RELATED INFORMATIONS
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