1. We need to decide how to celebrate your birthday,
2 You needn't to go to the shop. I have bought everything we need.
3. Pupils must wear uniforms at school. It's a rule!
4. They don't have to cook dinner. Mother has done it.
5. People mustn't cross the street when traffic lights are red!
6. You have to do morning exercises! It's very useful!
7. May I take your pen? I have lost my pen
8. My friend can't speak English, but he speaks French.
9. You shouldn't go out if you feel not very well.
10. I should to take my umbrella, it's raining
Объяснение:
the side surface of this pyramid consists of 6 isosceles triangles with a base 16 and a side 17.
Find the area of one triangle.
S = 1/2bh, where b is the base and h is the height.
The height is found by the Pythagorean theorem.
The height is equal to the square root of the difference between the squares of the side of the triangle and the half of the base. Half of the base 16 / 2 = 8
17*17 - 8*8 = 225. The square root of 225 is 15. The height of the triangle is 15. Then the area of the triangle will be equal to S = 1/2*16*15 = 120 and the area of the side surface of this pyramid is equal to the area of one triangle multiplied by 6. S1 = 120 * 6 = 720
Hi!
It is great to have a pet. I have a dog. I think that dogs are the best pets, they are the best friends. It is not difficult to look after him. His name is Baks. He is Labrador. I feed him in the morning and in the evening. And I walk with him 3 times a day. I like it. Of course when it rains or when it is cold it is not very comfortable to walk, but you must remember that you are responsible for your pet. So think before you get a pet. Do you live in a house or in the flat? Do you like dogs? Do you have much free time?
Write soon!
With love,
Nina