1, centerline

The line segment connecting the vertex of a triangle and the midpoint of its opposite side is called the midline of the triangle.

2, high

Draw a vertical line from the vertex to the line on the opposite side. The line segment between the vertex and the vertical foot is called the height of the triangle.

3. Angle dividing line

The bisector of the inner angle of a triangle intersects the opposite side of the angle, and the line segment between the intersection of the vertex and the angle is called the bisector of the triangle.

4. center line

The line connecting the midpoints of any two sides of a triangle is called the midline. It is parallel to the third side and equal to half of the third side.

Extended data:

Related calculation formula:

First, the perimeter formula

If the three sides of a triangle are A, B and C, then C = A+B+C B+C.

Second, the area formula

1, S= 1/2ah (area = bottom × height ÷2. Where A is the base of the triangle and H is the height corresponding to the base) Note: All three sides can be the base, which should be understood as: half of the product of the heights corresponding to the three sides is the area of the triangle. This is the basis of finding the length of line segment by area method.

2. s =1/2acsinb =1/2bcsina =1/2absinc (where the three corners are ∠A, ∠B, ∠C, and the opposite sides are ∠ a, b, c). See trigonometric function)

3, S=hl(l is the middle line of the high side)

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