Calculation formula of volume, surface area and side area of cone

Calculation formula of volume, surface area and side area of cone

Volume: 1 / 3 * bottom area * height
Side area: 3.14 (PI) * bottom radius * generatrix
(generatrix refers to the distance from the top of the cone to a point on the bottom of the cone)
Surface area (full area): side area + square of bottom radius * 3.14 (circumference)

On the surface area of a round table
In order to beautify the appearance of a flower pot, it is necessary to paint. It is known that 100 ml of paint is used per square meter, and how much paint is needed for the bath (π = 3.14, the result is accurate to 1 ml)?

To 999 ml paint flowerpot surface area = diameter 20, wall length (15 + x) cone side area - diameter 15, wall length x cone side area + diameter 15 circle area - diameter 1.5 circle area, and 15 / 20 = x / (x + 15) x = 45, so: flowerpot surface area = 3.14 (20 / 2) (15 + 45) - 3.14 (15 / 2) 45 + 3.14 (1

To find the surface area of a frustum Hurry!
The height of the frustum is 12, the length of the generatrix is 13, and the ratio of the radii of the two bottom surfaces is 3:8

Let R be the radius of the upper circle and R be the radius of the lower circle. The height is 12 and the generatrix is 13. According to the Pythagorean theorem, R-R = 5. The ratio of radius is 3:8. It can be seen that r = 3, r = 8, side area is s, side = π (R + R) l = π (3 + 8) × 13 = 143 π, upper radius s = π × R × r = 9 π, lower radius s = π × R × r = 64 π, surface area s = (143 + 9 + 64) π = 216 π