Materials/tools
Right-angled triangular ruler? Pen?
Specific steps?
1. Step 1: Select and determine one side of the triangle as the base, taking the BC side in the following figure as an example.
2. Step 2: Overlap the right angle edge of the triangular ruler with the bottom decomposition BC.
3. Step 3: Move the triangle ruler along the BC side so that the other right-angled side of the triangle ruler passes through the vertex A. ..
Step 4: Draw a vertical line from vertex A to its corresponding bottom BC.
5. Step 5: Remove the triangular ruler. The vertical line drawn above is the height of the BC side of the triangle.
6. Step 6: Repeat the above steps and draw the other two heights of the triangle based on AC and AB respectively.
Definition and drawing of triangle height
1, definition
Draw a vertical line from the vertex of a triangle to its opposite side (or the straight line where the opposite side is located). The line segment between the vertex and the vertical foot is called the height line of the triangle, which is called height for short.
So, by definition, the height of a triangle is a line segment. Because a triangle has three sides, it has three heights.
2. Painting method
Acute triangle: perpendicular from one vertex to the opposite side of the vertex.
The right side of the right triangle is the height of the right triangle, and the height of the hypotenuse is the height when the vertex of the right triangle is perpendicular to the hypotenuse.
Oblique triangle: the vertical line from the obtuse vertex to the opposite side is the height of this side, and the vertical line from the acute angle to the extension line of the opposite side is the height of this side.
3. Application scenarios
The height of a triangle is often used to calculate the area of a triangle, and the formula is area = (base length × height) ÷ 2;
In addition, the height of a triangle is often used to solve trigonometric functions, such as sine, cosine and tangent functions.
4. Precautions for drawing height
When drawing the height of a triangle, it needs to be perpendicular to the selected bottom and form a right triangle with the bottom * * *;
If the height is not perpendicular to the bottom edge, the correct height cannot be obtained; If the height and the base are not at right angles, you need to calculate the other two angles of the triangle, and then use trigonometric function to solve the height.
To sum up, to draw the height of a triangle, you need to determine a bottom and draw a straight line vertically upward from the vertex of this bottom. This operation can obtain the distance from any side of a triangle to its opposite side, which provides support for subsequent mathematical calculations.