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If the coordinates of the three vertices of a triangle are a (- - 5,2), B (1,2), C (3, - 10), then the area of triangle ABC
With ab as the bottom edge, the bottom edge is 6 long, 12 high, and area: 6 * 12 * 0.5 = 36
The coordinates of the three vertices a, B and C of triangle ABC are a (2, - 1), B (1, - 3) and C (4, - 3.5) respectively. Find the area of this triangle ※ please write down the process,,, →＾＾←
Draw a drawing and construct a rectangle. Subtract the area of three right triangles from the rectangular area (calculate the side length and area according to the coordinates). The area is 6-3 / 2-1 / 2-2 = 2
As shown in the figure, the three vertex coordinates of triangle ABC are a (- 2,3), B (- 4, - 1) and C (2,0) to calculate the area of triangle ABC
The equation of a (- 2,3), B (- 4, - 1) straight line AB is y = 2x + 7 when y = 0, x = - 7 / 2
Area of triangle ABC = (2 + 7 / 2) x (3 + 1) = (11 / 2) X4 = 22
As shown in the figure, the vertex coordinates of triangle ABC are a (2, - 1), B (4,3) C (1,2) respectively. Find the area of ABC
BC length is (4-1) ^ 2 + (3-2) ^ 2 = root 10 (this is the distance formula between two points)
Then find the linear analytical formula of BC
Let LBC: y = KX + B
Substitute the coordinates of B and C into the equation
2=k+b,3=4k+b
Find k = one-third, B = five-thirds
So LBC: y = 1 / 3x + 5 / 3
That is, x-3y + 5 = 0
Then find the distance from a to BC
The distance formula from the applied point to the straight line is
Absolute value of distance d = 2 + (- 3) * - 1) + 5 / 1 ^ 2 + 3 ^ 2 = root 10
So area = 0.5 * BC * d = 5
In the right angle triangular coordinate system as shown in figure 12.1-4, the area of the triangle is calculated from the coordinates a (- 1,3) B (- 2, - 1) C (2,0) of each vertex of triangle ABC The best answer is today
As shown in the figure, divide the triangle into two parts
The upper half of the Y axis is a part and the lower half is a part
Make vertical lines from two points a and B to the X axis to obtain two high lines with lengths of 3 and 1 respectively
The line AB equation 4x-y + 7 = 0 is obtained from the two-point coordinates of AB, and the intersection D (- 7 / 4,0) of AB line and X axis is obtained by making y = 0
Therefore, the length of DC is 15 / 4
S=(15/4*3)/2+(15/4*1)/2
=15/2
In the rectangular coordinate system as shown in the figure, the coordinates of the vertices of triangle ABC are a (- 1,3), B (- 2, - 1), C (2,0), and calculate the area of triangle ABC
eight
4*（1+3）/2=8
RELATED INFORMATIONS
- 1. It is known that the coordinates of each vertex of triangle ABC are a (- 1,3) B (- 2, - 1) C (2,0) respectively. Find the area of triangle?
- 2. In triangle ABC, the side length of the inner angle ABC is ABC respectively. It is known that C = 2 and C = 60 degrees. If SINB = 2sina, if the area of triangle ABC is equal to root 3
- 3. An organic substance A is composed of C, h and O. under certain conditions, the transformation relationship between a, B, C, D and E is as follows: It is known that the vapor density of C is 22 times that of hydrogen under the same conditions, and silver mirror reaction can occur (1) The name of the functional group contained in substance D is __, The structural formula of substance e is ___, (2) Write the chemical equation to achieve the following conversion: ①A→B______， ②A+O 2 →C______ ③ C equation for reaction with silver ammonia solution ___
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- 9. In triangle ABC, A.B.C is the length of the side opposite angle A.B.C, and S is the area of triangle ABC Know s = a Λ 2 - (B-C) Λ2. Find Tana
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- 13. What is the purpose of a bicycle to increase friction and what is to reduce friction What parts?
- 14. In RT triangle ABC, angle c = 90 degrees, the opposite sides of angle a, angle B and angle c are a, B and C respectively. Let the area of triangle ABC be s and the perimeter be L Then S / L = (a + B-C) / 4, explain the reason for this conclusion
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- 16. In triangle ABC, a, B and C are the opposite sides of angle a, angle B and angle C respectively. If 2B = a + C, angle B = 30 °, the area of triangle ABC is 1 / 2, then B is?
- 17. In triangle ABC, angle c is equal to 90 degrees, angle a is equal to 15 degrees, and BC is equal to 4. Find the area of triangle ABC The figure is a single triangle
- 18. The ratio of inscribed circle radius to circumscribed circle radius of triangles with side lengths of 3, 4 and 5 is () A. 1：5 B. 2：5 C. 3：5 D. 4：5
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