About commonly used area volume calculation formula, what good software is better, thank you for your advice! I want to calculate the volume of a standard elliptical head and determine its weight

About commonly used area volume calculation formula, what good software is better, thank you for your advice! I want to calculate the volume of a standard elliptical head and determine its weight

In my opinion, first of all, you need to know the basic formulas for calculating the area of triangles, rectangles, squares, circles and sectors,
When calculating the surface area, you add up the area of each surface (here, you also need to remember to expand the side view of some things, for example, the side view of a cylinder is rectangular, and the side view of a cone is fan-shaped)
In the calculation of volume, the bottom area is usually multiplied by the height, but the cone should be multiplied by 1 / 3, etc

If the surface area of a cone is 27 π m2 and its side view is a semicircle, then the bottom of the cone is straight

Let l be the generatrix of the cone and R be the radius of the circle at the bottom of the cone
Then: (because the side expansion is semicircle, the area of the side expansion is & # 189; π L & # 178;, the bottom area is π R & # 178;, and the surface area is known as 27 π) &# 189; π L & # 178; + π R & # 178; = 27 π ①
2 × L = 2 × π × R 2 (if the side view is semicircle, it is "diameter" range = circumference of the bottom circle)
The simultaneous expressions of (1) and (2) give R & # 178; = 27 / (# 189; × π & # 178; + 1)
Diameter d = 2 × R ≈ 9.1

Given that the surface area of a cone is a, and its side expansion is a semicircle, find the bottom diameter of the cone
My idea: let the diameter length be L. s side = Πrl = Π × L / 2 × L / 2 = Πl ^ 2 / 4. S bottom = Πr ^ 2 = Πl ^ 2 / 4
, s table = s side + s bottom = Πl ^ 2 / 2 = a, and then calculate l according to this formula?

It's on your s side (my 3.14 sign can't be typed out, use ￥ instead of below) formula s side = ￥ RL = ￥ (￥ L △ ￥) (￥ L) = ￥ 2 × L ^ 2
The key is to use mixed symbols
Side R ≠ bottom R

The radius of circle a is four times that of circle B, the perimeter of circle a is () times that of circle B, and the area of circle a is () times that of circle B

Circumference C = 2 π R, so the circumference of circle a is four times that of circle B
Area s = π R & sup2;, so the area of circle a is 4 & sup2; times that of circle B, that is 16 times

The diameter of circle a is equal to the radius of circle B. ① write the perimeter ratio of circle a and circle B. ② write the area ratio of circle B and circle a
The diameter of circle a is equal to the radius of circle B
① Write out the circumference ratio of circle a and circle B
② Write the area ratio of circle B to circle a

1:2
1:4

The radius of circle a is three times that of circle B. the perimeter of circle B is () of circle a, and the area of circle B is ()

The radius of circle a is three times that of circle B. the perimeter of circle B is 1 / 3 of circle a and the area of circle B is 1 / 9 of circle a

The perimeter difference of two circles is 94.2. The radius of the big circle is twice that of the small circle. The area sum of the two circles is calculated

Circumference of small circle: 94.2 ÷ (2-1) = 94.2
Radius of small circle: 94.2 △ 3.14 △ 2 = 15
Radius of great circle: 15 × 2 = 30
Small circle area: 3.14 × 15 × 15 = 706.5
Large circle area: 3.14 × 30 × 30 = 2826
Area sum of two circles: 706.5 + 2826 = 3532.5

The sum of the circumference of the two circles is 18.84 cm. It is known that the radius of the big circle is twice that of the small circle. How many square centimeters are the areas of the two circles?

Small circle area = 18.84 △ 1 + 2 = 6.28cm
Radius of small circle = 6.28 △ 3.14 △ 2 = 1cm
Small circle area = 1 × 1 × 3.14 = 3.14 square centimeter
Small circle area: large circle area = 1:4
Large circle area = 3.14 × 4 = 12.56 square centimeter

The sum of the circumference of the two circles is 94.2 cm. It is known that the ratio of the radius of the big circle to the radius of the small circle is 4 ∶ 1. How many square centimeters are the areas of the two circles?

Let the radius of the small circle be r, then the radius of the big circle be 4R
2πr+2π*4r=94.2
The solution is r = 3
So the area of the small circle is π R ^ 2 = 28.26
The area of the great circle is π (4R) ^ 2 = 452.16

The perimeter ratio of a and B circles is 3:4. The area of one circle is 15 square centimeters, and the area of the other circle may be (), or ()

The perimeter ratio of a and B circles is 3:4, and the area of one circle is 15 square centimeters,
The area of another circle may be (80 / 3) or (135 / 9)
The perimeter ratio of a and B is 3:4
The area ratio of a and B is 9:16
15×16/9=80/3
15×9/16=135/16
(*^__ ^* *^__ ^* *^__ ^*Hello, it's my greatest happiness to be able to help you!