![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
We know that ad = BD, AE = BC, the area of triangle ABC is 40 square decimeters, what is the area of shadow? The shadow is connected by DEB
In this figure, we can consider that ABC and Abe are triangles with the same base and height, so they have the same area
So the area of bed is abd + Abe, that is to say, the area of bed is equal to the area of ABCD
As for the area method of abd, it should be calculated according to the figure. The area of triangles with the same base and height should be equal
OC is a ray outside ∠ AOB, OD bisects ∠ BOC, OE bisects ∠ AOC to find ∠ doe
OC is a ray outside ∠ AOB, OD bisects ∠ BOC
OE bisecting ∠ AOC finding ∠ doe
∠AOB=80°
Assuming that ∠ AOB = 60, ∠ BOC = 30, from od bisection ∠ BOC OE bisection ∠ AOC, we can see that ∠ EOB = 15, ∠ BOD = 15, and ∠ doc = ∠ EOB + ∠ BOD = 30, i.e. ∠ DOE = 1 / 2 ∠ AOB
How many meters is it from Xiaoli's house to Cultural Palace?
"S/75+S/50=36
RELATED INFORMATIONS
- 1. It's good to enjoy the cool under the big trees. The destruction of a thousand mile dike in an ant colony shows that organisms and the environment interact with each other?
- 2. The reason why it is good to enjoy the cool under the big trees is that: (1) The big tree has a big crown and a big shade (2) During the day, the air under the big trees is fresh because (3) In hot summer, the air under big trees is wetter and cooler than other places. The reason is that
- 3. The reason of enjoying cool under big trees is explained by transpiration
- 4. Xiao Li is 27 years younger than her mother, and her father is 4 years older than her mother. The total age of the three is 82. How old is Xiao Li this year
- 5. Congcong made a round greeting card for her teacher with colored cardboard. In order to be beautiful, she bought a colored rope to stick it to the outside of the card. The card shared 31.4cm colored rope. Do you know how many square centimeters of colored cardboard she used? Come on. Give me the answer in 6 minutes
- 6. Playing card game: Xiao Ming's back to Xiao Liang, let Xiao Liang operate according to the following four steps: the first step & nbsp; distribute the left, middle and right three piles of cards, each pile has the same number of cards, and no less than two cards; the second step & nbsp; take out two cards from the left pile and put them in the middle pile; the third step & nbsp; take out one card from the right pile and put it in the middle pile; the fourth step & nbsp; There are several cards in the left pile, so take a few cards from the middle pile and put them into the left pile. At this time, Xiao Ming accurately said the current number of cards in the middle pile. What do you think is the current number of cards in the middle pile? Explain your reasons
- 7. There are 2 yuan, 5 yuan and 6 yuan coupons in the playground. Xiaogang bought 15 coupons and spent 58 yuan. It is known that the number of 5 yuan and 6 yuan coupons is the same. Xiaogang bought 2 yuan, 5 yuan and 6 yuan coupons How many each?
- 8. Xiaogang and Xiaoli jump rope. Xiaogang jumps 240 times. The number of Xiaoli is 3 / 8 of Xiaogang's. how many times did they jump together?
- 9. There are four playing cards with 10, 9, 8, 7 points. Dongdong and Jiajia touch once respectively. Who has the most points wins? Is the game fair? Please explain the reason
- 10. 1. The stamp ratio of Xiao Ming and Xiao Li is 1:4. Xiao Ming has 72 fewer stamps than Xiao Li. How many stamps does Xiao Li have 2. Suppose that the ratio of salt to water in brine is 1:9, then salt accounts for ()% (write the answer directly) 3. The scale of a part drawing is 7:1. If the length of the part measured on the drawing is 49mm, how many mm is the actual length 4. The survey team measured the height of the TV Tower and got the shadow length of 45 meters. At the same time, the shadow length of a 10 meter high column nearby was 2 meters. What's the height of the TV Tower? (to give the formula)
- 11. In △ ABC, D is a point on the edge of BC, and BD: DC = 3:2, e is a point on the edge of AC. be and ad intersect point O, and Bo: OE = 4:1, the value of Ce: EA is obtained
- 12. As shown in the figure, in the triangle ABC, the angle c = 90 degrees, AC = BC, ad bisector angle BAC, intersection BC at point D, de vertical AB, perpendicular foot E. try to explain the reason why AB = AC + CD
- 13. In △ ABC, ∠ C = 90 °, ab = 13, BC = 5, then the radius of its circumscribed circle is______ The radius of the inscribed circle is______ ．
- 14. The center of gravity in the triangle ABC is g, GA = 2 times the root 3, GB = 2 times the root 2, GC = 2, and the area of the triangle GBC is calculated
- 15. Δ ABC is an isosceles triangle with known angle a = 20 ° and angle B =?
- 16. As shown in the figure, in isosceles △ ABC, the bisectors of ∠ a = 80 °, B and C intersect at point O (1) to connect OA, and then calculate the degree of ∠ OAC; (2) to calculate: ∠ BOC
- 17. As shown in the figure, in the isosceles △ ABC, AC = BC = 10, take BC as the diameter, make ⊙ o, intersect AB at point D, intersect AC at point G, DF ⊥ AC at point F, and intersect the extension line of CB at point E. (1) prove that the straight line EF is the tangent of ⊙ o; (2) if sin ∠ e = 25, find the length of ab
- 18. In RT triangle ABC, angle c = 90 degrees, G is the center of gravity, ab = 12, CG =?
- 19. Eight thin steel plates are 2.4m long and 1m wide, weighing 6kg. Cut a disc with d = 80cm from the top. How much does the disc weigh? It's a thin steel plate. It's wrong. It's not eight I need a process
- 20. As shown in the figure, C is the midpoint of line AB and D is the midpoint of line AC. given that the sum of the lengths of all line segments in the figure is 23, the length of line AC is calculated A———D———C——————B It's due this afternoon. Hurry up