How to write a lesson plan for the perimeter and area of a triangle

Answer: [Triangle circumference: the sum of the three sides;

Triangle area: base height 2

TriangularArea formulais the base height 2. The formula for the circumference of a triangle is: c=a+b+c.

where c represents the perimeter, and a, b, and c are the three sides of the triangle, respectively. Isosceles trianglec=2a+b，Equilateral trianglesc=3a。

1. The formula for the perimeter of a triangle.

If the three sides of a triangle are a, b, and c, and the circumference is c, then c=a+b+c.

2. The area formula of the triangle.

1. S= Ah area Bottom height 2 (S is the area of the triangle, A is the base of the triangle, and H is the height corresponding to the base).

2. s= acsinb= bcsina= acsinb (where the three angles are a, b, c, and the opposite sides are a, b, c. ）。

3. s=hl (where l is the median line of the side where the height is located).

4. S=RP (where r is the radius of the inner orange book, and p is the half-circumference).

5. S=Rr(Sina+Sinb+Sinc) (where r is the radius of the circumscribed circle; r is the radius of the inscribed circle).

Nature of the Triangle:

1. The sum of the internal angles of the triangle on a plane is equal to 180° (the sum of internal angles theorem).

2. The outer corner of the triangle on the plane.

The sum is equal to 360° (the sum of the outer angles theorem).

3. The sum of any two sides of the triangle is greater than the third side, and the attitude carrying difference of any two sides is less than that of the third side.

4. The outer angles of a triangle on a plane are equal to the sum of the two inner angles that are not adjacent to it.

5. In a right triangle.

, if an angle is equal to 30 degrees, then the right-angled side opposite the 30-degree angle is hypotenuse.

of half. 6. The sum of the squares of the two right-angled sides of a right-angled triangle is equal to the square of the hypotenuse (Pythagorean theorem.

7. The middle line of the hypotenuse of a right triangle is equal to half of the hypotenuse.

8. The angular bisector of the apex of an isosceles triangle.

It is in a straight line with the height on the bottom edge and the middle line on the bottom edge (three lines in one).

The perimeter of a triangle is the integral of the length around the edge of a finite area, which is the length of a circle around the figure. The area of a triangle refers to the size of the planar figure occupied by the object.

Triangle circumference: If the three sides of a triangle are a, b, and c, then c=a+b+c. The area of the triangle.

s = 1 2ah (area = base times height divided by 2, a is the base of the triangle, h is the height corresponding to the base), all three sides can be the base, and half of the product of the corresponding high of the three sides is the area of the triangle.

Three-dog leakage angular classification

1. Unequal triangles.

A triangle with three unequal sides.

2. Isosceles triangle.

A triangle with equal sides, and two equal sides are called the waist of this triangle. In an isosceles triangle, the two equal sides are called the waist of the triangle, and the other side is called the missing bottom edge.

3. Equilateral triangles. An equilateral triangle (also known as a regular triangle, is a triangle with three equal sides, and its three internal angles are equal, all 60°, it is an acute triangle.

one. Equilateral triangles are also the most stable structure. Equilateral triangles are special isosceles triangles, so equilateral triangles have all the properties of isosceles triangles.

The above information reference: Encyclopedia - Triangle.

The area of the triangle has nothing to do with its perimeter. Because the circumference of the triangle = a + b + c (a, b, c are the three sides of the triangle respectively), the area of the triangle = 1 2ah (a is the length of the base, h is the height of the base).

A triangle is a closed figure composed of three line segments in the same plane that are not on the same straight line in order to end, which has applications in mathematics and architecture.

TriangularArea formulais the base height 2. The formula for the circumference of a triangle is: c=a+b+c.

where c represents the perimeter, and a, b, and c are the three sides of the triangle, respectively. Isosceles trianglec=2a+b，Equilateral trianglesc=3a。

Nature of the Triangle:

On a plane, the sum of the inner angles of the triangle is equal to 180 degrees; The outer corner of the triangle on the plane spike.

The sum is equal to 360° (the sum of the outer angles theorem). The sum of any two sides of the triangle is greater than the third side, and the difference between any two sides is less than the third side; On a plane, the outer angles of a triangle are equal to the sum of the two inner angles that are not adjacent to it; in a right triangle.

, if an angle is equal to 30 degrees, then the right-angled edge opposite by the 30-degree angle is an hypotenuse.

of half. The sum of the squares of the two right-angled sides of a right-angled triangle is equal to the square of the hypotenuse, and the midline of the hypotenuse of a right-angled triangle is equal to half of the hypotenuse; The angular bisector of the apex of an isosceles triangle.

It is in a straight line with the high on the bottom edge and the middle line on the bottom edge.

If the three sides of a triangle a, b, c (a ruler is good c 2, then the triangle is an acute triangle; a 2 + b 2 = c 2, then this triangle is a right triangle; A 2 + B 2 obtuse triangles.

The perimeter of the triangle: the sum of the three segments of the triangle; Area of the triangle: The base edge of the triangle multiplied by the height of the triangle divided by two.

The bottom represents the bottom part, the base layer of the pattern, or the end. Make a perpendicular line from a vertex in the shape of a triangular potato to its opposite edge.

Then the line segment between this vertex and the perpendicular foot is called the high line of the triangle, which is simply called high.

Characteristics of similar triangles:1. The sides of similar triangles should be proportional to the sides of the pants rock, and the corresponding angles should be equal.

2. The ratio of the corresponding sides of a similar triangle is called the similarity ratio.

Number of dates. 3. The circumference ratio of a similar triangle is equal to the similarity ratio, and the area ratio is equal to the square of the similarity ratio.

4. Similar triangles correspond to line segments (angle bisector lines.

midline, high) is equal to the similarity ratio.

The area of the triangle is half the height of the base.

The circumference of the triangle is the sum of the three lengths a+b+c

The triangle area formula is base height 2. The circumference of a triangle is the sum of the lengths of the three sides, i.e., a+b+c.

A triangle is a closed figure composed of three line segments in the same plane that are not on the same straight line in order to end, which has applications in mathematics and architecture. Common triangles are divided into ordinary triangles (the three sides are not equal) and isosceles triangles (isosceles triangles with unequal waists and bases, and isosceles triangles with equal waists and bottoms, that is, equilateral triangles); According to the angle, there are right triangles, acute triangles, obtuse triangles, etc., of which acute triangles and obtuse triangles are collectively referred to as oblique triangles. All triangles apply to the above formula.