It will be introduced in detail below, including mathematical concepts and functions.
1, definition
A triangle is a figure composed of three line segments, including the concepts of base, height and hypotenuse. In a triangle, perimeter refers to the sum of three sides, that is, perimeter = side 1+ side 2+ side 3.
2. Formula formula
The formula of triangle perimeter that primary school students need to master is "perimeter plus side length", that is, the sum of the lengths of three sides of a triangle is the perimeter of the triangle.
3. Application
From primary school, when calculating the perimeter of a triangle, the formula of "side length plus perimeter" can be easily solved. In addition, when learning higher-level mathematical concepts, such as Pythagorean theorem, sine function, etc. The triangle perimeter formula will also be more widely used.
4. Expanding knowledge: triangle classification
Besides calculating the perimeter of triangle, understanding the classification of triangle is also an important content of primary school mathematics. According to the different standards of three sides length, angle size and angle difference, triangles can be divided into equilateral triangles, isosceles triangles, right triangles, acute triangles and obtuse triangles.
5, the nature of the triangle
In addition to classification, understanding the nature of triangles is also an important content of primary school mathematics. Common triangle attributes include:
"theorem of sum of two angles": the sum of the degrees of two angles in a triangle is equal to the degree of the third angle.
"Equiangular sides have equal proportions": in an equilateral triangle, the ratio of two sides is equal to the sine of the corresponding internal angle.
"The bisector, midline and height of an isosceles triangle intersect at one point": In an isosceles triangle, the bisector, midline and height intersect at one point.
6. Problem-solving skills
When solving the problem of triangle perimeter, we can consider different methods according to different situations. For example, given the length of three sides, we can directly use the formula of "side length plus perimeter" to solve it; But if we only know the length of two sides and their included angle, we need to use Pythagorean theorem, sine function and other methods to derive.
7. Summary
The triangle perimeter formula is one of the basic concepts in primary school mathematics, and mastering it is very important for laying a good foundation for mathematics. Knowing the classification and nature of triangles can enrich our mathematical knowledge and improve the efficiency and accuracy of solving problems.
Summary: The formula of triangle perimeter in primary school is "perimeter plus side length", which is one of the foundations of primary school mathematics. Understanding the classification of triangles is also an important mathematical knowledge. Mastering this kind of knowledge skillfully is very helpful for laying a good foundation of mathematics and expanding mathematical thinking.