In this compilation of formulas for calculating the surface area and volume of a cone, Mytour will introduce and share detailed insights into the formulas for calculating the surface area and volume of a cone, including calculation methods and specific examples.
The cone with vertex A is formed by rotating triangle OAC about O, with OA edge fixed. Readers can refer to the Wikipedia article on cones for further understanding.
1. Formulas and method for calculating the surface area of a cone
1.1. Formula for calculating the lateral surface area of a cone: The lateral surface area of a cone equals the product of the base radius and the slant height, multiplied by the value of Pi.
Slateral = π x r x l
Where:
- r : The radius of the base of the cone.
- l: The slant height of the cone.
- π: The value of Pi (approximately 3.14).
* Example of calculating the lateral surface area of a cone:
Given any cone with the base at point O and the vertex at point A. The radius r is 6cm. What is the lateral surface area of the cone, knowing that the length of the slant height connecting vertex A to any point on the base is 8cm?
Continuing to apply the formula for calculating the lateral surface area of a cone, we have:
Sxq = π x r x l = π x 6 x 8 = 150.72 (cm2).
The answer after applying the formula for calculating the lateral surface area of a cone is 150.72 cm2.
1.2. Formula for calculating the total surface area of a cone: The formula for calculating the total surface area of a cone is the product of the base radius and the slant height, multiplied by the value of Pi.
Stotal = Sxq +Sbase = π x r x l + π x r2
In which:
- r : The radius of the base of the cone.
- l : The length of the slant height of the cone.
- π: the value of Pi (approximately 3.14).
* Example of calculating the total surface area of a cone
Similar to the example above, but replacing the radius r value with 6cm. The slant height is 8cm. What is the total surface area of the cone?
Applying the formula for calculating the surface area of a cone, we have:
Total surface area = π x r x l + π x r2 = π x 5 x 7 + π x 52 = 188.4 (cm2).
So after applying the method for calculating the total surface area of the cone above, we have the answer as 188.4cm2.
2. Formulas and method for calculating the volume of a cone
* Formula for calculating the volume of a cone
V = 1/3 x π x r2 x h
Where:
- r : The radius of the base of the cone.
- h : The height from the base to the vertex of the cone.
- π: the value of Pi (approximately 3.14).
* Example of calculating the volume of a cone
Using a similar approach to the previous question, however, we change some values of the cone including the radius r being 7cm, and the height from the base to the vertex of the cone being 9cm. What is the volume of this cone?
Using the formula for calculating the volume of a cone, we have:
V = 1/3 x π x r2 x h = 1/3 x π x (7x7) x 9 ~ 462 cm3.
Here are the complete formulas for calculating the surface area and volume of a cone. Understanding these formulas is crucial for solving cone-related problems in both academic and real-life contexts.
Especially in many complex problems that require combining formulas for calculating the area of squares or the volume of cubes, cylinders, if you grasp the relationships in the formulas for calculating the surface area and volume of a cone and the formulas for calculating the area of squares, you can easily find missing values if the problem does not provide them.
Along with solid geometry, cylinders, and cubes are widely used. Among them, the formulas for calculating the volume of cubes and cylinders are the most commonly required and are always applied in challenging, high-scoring problems. With the formulas for calculating the surface area and volume of a cone provided in this article, readers will have a basis for solving more difficult problems.
A rectangular prism is also one of the geometric shapes you have to study. The method of calculating the volume of a rectangular prism is relatively easy to understand. If you are unfamiliar with the formula for calculating the volume of a rectangular prism, please follow the article on Mytour for the exact formula.