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As shown in the figure, the straight lines a and B are cut by the lines C and D, ∠ 1 and ∠ 2 are complementary angles to each other, ∠ 3 = 117 ° and the degree of ∠ 4 is calculated
∵∠5=180°-∠3=180°-117°=63°
And ∵ 1 and ∵ 2 are complementary angles to each other,
∴a∥b，
∴∠4=∠5=63°．
As shown in the figure, it is a 4 * 4 square. Calculate the degree of angle 1 + angle 2 + angle 3 +. + angle 16 Give high marks if you can answer
There are 8 pairs of complementary angles, i.e., 8 × 90 ° = 720 ° for each other
Is every octagon of 135 degrees positive?
∵ each external angle of the regular octagon is: 360 ° / 8 = 45 °,
Each internal angle is 180 ° - 45 ° = 135 °
Given two regular polygons, the ratio of their sides is 1:2, and the ratio of inner angle and degree is 3:8, find their respective number of sides By the way, the sum of all the interior angles of a polygon is 1680 ° except one inner angle. Find the degree of this angle and the number of sides of the polygon What's central symmetry?
Rotation 180 ° and the original figure coincide with the center symmetry figure
1) 5-Sided and 10-sided
2) Take 180 and multiply it slowly --
Determine the degree of the angle between the hour and the minute on the corresponding clocks in four cities: 1:12:8:9:00
30°；0°；120°；90°
The degree of an angle of an equilateral triangle is ()% of the degree of an angle of a square Band formula
The degree of one angle of an equilateral triangle is 180 / 3 = 60 degrees,
The degree of one corner of a square is 360 / 4 = 90,
So the proportion is: 60 / 90 * 100% = 66.7%
As shown in the figure, it is known that the straight lines AB and CD intersect at point O, OE bisects ∠ BOD, if ∠ 3: ∠ 2 = 8:1, Find the degree of ∠ AOC
∵ bisection ∵ BOD,
∴∠1=∠2，
∵∠3：∠2=8：1，
∴∠3=8∠2．
∵∠1+∠2+∠3=180°，
∴∠2+∠2+8∠2=180°，
The solution is ∠ 2 = 18 °,
∴∠AOC=∠1+∠2=36°．
As shown in the figure, the straight lines AB and CD intersect at O, OE bisection ∠ AOC, ∠ BOC - ∠ BOD = 20 ° and find the degree of ∠ BOE
∵ BOC - ∠ BOD = 20 ° and ∠ BOC + ∠ BOD = 180 °,
∴∠BOC=100°，∠AOC=80°，
∵ OE bisection ∵ AOC,
∴∠EOC=1
2∠AOC=40°，
∴∠BOE=∠BOC+∠EOC=140°．
As shown in the figure, it is known that the straight lines AB and CD intersect at point O, OE bisects ∠ BOD, if ∠ 3: ∠ 2 = 8:1, Find the degree of ∠ AOC
∵ bisection ∵ BOD,
∴∠1=∠2，
∵∠3：∠2=8：1，
∴∠3=8∠2．
∵∠1+∠2+∠3=180°，
∴∠2+∠2+8∠2=180°，
The solution is ∠ 2 = 18 °,
∴∠AOC=∠1+∠2=36°．
As shown in the figure, the straight line AB and CD intersect at the point O, known as ∠ AOC = 70 ° and OE divides ∠ BOD into two parts, BOE: ∠ EOD = 2:3, calculate the degree of EOD
The angle AOC and the angle BOD are opposite vertex angles, so the angle BOD = 70 ° and ∠ BOE = 2x, then ∠ EOD = 3x
So 5x = 70, x = 14, ∠ EOD = 42 °
RELATED INFORMATIONS
- 1. The lines AB and CD intersect at o.oe and of are bisectors of angle AOC and angle BOD respectively. (1) draw the figure. (2) ray OE The lines AB and CD intersect at points o.oe and of are bisectors of angle AOC and angle BOD respectively. (1) draw this figure. (2) are ray OE and of on the same line? (3) draw bisector of angle AOD OG.OE What is the location relationship with og?
- 2. As shown in the figure, in △ ABC, D is a point on the edge of BC, ∠ 1 = ∠ 2, ∠ 3 = ∠ 4, ∠ BAC = 63 ° to find the degree of angle DAC
- 3. As shown in the figure, in △ ABC, ∠ ABC = ∠ C = 2 ∠ a, BD ⊥ AC intersects AC at point D, then ∠ DBC=______ .
- 4. As shown in the figure, we know ∠ 1 + ∠ 2 = 180 ° and ∠ 3 = ∠ B. try to judge the size relationship between ∠ AED and ∠ C, and rationalize the conclusion
- 5. As shown in the figure, AB / / CD, ad vertical DC, ab = BC, and AE vertical BC 1. Prove that ad = AE If ad = 8, DC = 4, the length of AB is 4
- 6. (Mathematics) in RT △ ABC, ∠ B = 90 degrees, BC > AB, BP = ba, BP=BA,BD⊥AC,PE⊥AC In the four line segments ad, BD, De, PE, there is a certain quantitative relationship between some line segments. Please write an equation to express the quantitative relationship (the equation contains 2 or 3 line segments), and explain the reasons for the equation
- 7. In the triangle ABC, the angle c = 90 degrees, AC = BC, P is any point of AB, PE is vertical BC, PF is vertical AC, M is the midpoint of AB, connecting me, MF It is proved that me = MF
- 8. Given that the triangle ABC, P is a point in the triangle, through P as PD vertical BC, PE vertical AC, PF vertical AB, the height of triangle ABC h, it is proved that PD + PE + pf = H
- 9. In the RT triangle ABC, ∠ C = 90 ° C = 34. If a to B is equal to 8 to 15, then a = b =
- 10. In Baidu RT triangle ABC, angle c = 90 degrees, angle a = 30 degrees, AC = 2
- 11. As shown in the figure, in trapezoidal ABCD, ad ‖ BC, ∠ a = 90 °, e is the point above AB, EC = ed, ∠ BEC = 75 °, AED = 45 °, verification: ab = BC
- 12. As shown in the figure, is the line AB parallel to CD? And the line AD and BC? Why? Because of what, so what
- 13. As shown in the figure, AC bisects ∠ DAB, ab ＞ ad, CB = CD, CE ⊥ AB in E, (1) Results: ab = AD + 2EB; (2) If ad = 9, ab = 21, BC = 10, find the length of AC
- 14. In the triangle ABC, if the angle c is equal to 90 degrees, AC is equal to 8 times the root sign 3, and ab is equal to 10 times the root sign 3, what is the value of Tana
- 15. In △ ABC, the opposite sides of angles a, B and C are a, B, C. 2Sin? C = 3cosc, C = √ 7, and the area of △ ABC is (3 √ 3) / 2, ① The size of angle c; ② The value of a + B
- 16. In the triangle ABC, the angle B = 90 ', the two right sides AB = 7, BC = 24. There is a point P in the triangle whose distance from each side is equal. What is the distance?
- 17. Tan (- 2 π / 3) is equal to The value of Tan (- π / 3)
- 18. If sin θ + cos θ = √ 2, then Tan (θ + π / 3)
- 19. If Tan α = 2, cos (α + π) is equal to
- 20. Given that the final edge of the angle a passes through the point P (- √ 3, y) (Y ≠ 0) and sin a = √ 2 / 4 · y, find the values of COS A and Tan a