Công thức tính số đường chéo : \(\frac{n\left(n-3\right)}{2}\) trong đó n là số cạnh của đa giác.
Cách chứng minh ( tham khảo bên web khác ):
Tại đây. Từ đó đáp án là : \(\frac{36.33}{2}=594\)
Vậy ...
how many fingers are there in your hand ?
Choose the correct word marked A,B, or C to fill each blank in the following passage.(Why)
There are many reasons (1) ____ it is important to have a hobby. First of all, a hobby can be a remedy for your (2) ____. Because it is the activity you choose for yourself, it will always give you pleasure and (3) ____ you relax. Even if you just spend a little time enjoying your hobby, you can see the difference (4) ____ your spirit. Second, some hobbies can also (5) ____ you financially. Many old people enjoy gardening. They grow a lot of trees and vegertable, so they can sell them for some money. In (6) ____, a hobby can help you connect with other people. If you like colecting stamps, you can (7) ____ a stamp club to share your albums with other collectors. If your hobby is caving eggshells, you can give your products to your friends (8) ____ gifts.
1. A.for B. why C.because
2. A.happiness B.pain C.tiredness
3. A.help B. have C. do
4. A. for B. in C. on
5. A.harm B.give C.benefit
6. A. addition B. general C.conclusion
7. A.take part B.go C. join
8. A. like B.as C.for
The sides of a triangle are a, b and c respectively. What is the perimeter of the triangle if a = 5cm, b = 4cm, and c = 3cm? Answer: The perimeter of the triangle is cm.
đổi câu thành câu gián tiếp!
. “How many classes are there in your school?” The examiner said to Paola
how many numbers are there when divided by 9, the quotient and the remainder are the same ? Answer: there are.....numbers
Let I be the incentre of acute triangle ABC with \(AB\ne AC\). The incircle \(\omega\)of ABC is tangent to sides BC, CA and AB at D, E, F respectively. The line through D pependicular to EF meets \(\omega\)again at R. Line AR meets \(\omega\)again at P. The circumcircles of triangles PCE and PBF meet again at Q. Prove that lines DI and PQ meet on the line through A perpendicular to AI.
Let I be the incentre of acute triangle ABC with \(AB\ne AC\). The incircle \(\omega\)of ABC is tangent to sides BC, CA and AB at D, E, F respectively. The line through D pependicular to EF meets \(\omega\)again at R. Line AR meets \(\omega\)again at P. The circumcircles of triangles PCE and PBF meet again at Q. Prove that lines DI and PQ meet on the line through A perpendicular to AI.
The first time Bill looked at the clock it was 2.00 pm. Later that afternoon he saw it was 4.00 pm. Through how many degrees had the minute hand turned in this time?
Giúp mình làm các câu hỏi này nha: (càng nhiều càng tốt!)
1. Tiffany and Ryan deposit some amount in a joint bank account such that total balance remains 500. If amount deposited by Tiffany and Ryan are plotted as a linear graph on xy plane, find the area between this graph and the coordinate axis.
2.A group of workers is paving a road. If they pave 200m of the road a day, they will need 3 more days. to finish the work. If they pave 240m of the road a day, they will finish the work 2 days in advance. How long is the road, in meter?
3. Mrs. Darlie has a silver ring, a golden ring and a diamond ring. She put them on her left hand. Each ring can be on any of the five fingers. When there are two or three rings on the same finger, if the order in which they are put is different, that couunt as a different way. How many different ways for Lea to put these rings?
4. Let P(x) be a polynomial with degree 3 such that P(1)=3, P(2)=3, P(3)=7, P(4)=21. Find the value of P(5).
