## anonymous one year ago What are scale drawings? Can you give an example?

1. anonymous

@texaschic101

2. anonymous

@Michele_Laino

3. anonymous
4. anonymous

in your own words please :) and i need the example in words

5. Michele_Laino

scale drawings are drawings which refer to real objects, nevertheless their measures are reduced with respect to the corresponding real measures according to a scale factor. An example are the geographical maps

6. anonymous

Awesome.. can you give me another example?

7. Michele_Laino

another example are drawings used in order to design a mechanical construction, namely boats, race cars, planes, and so on

8. anonymous

can you give me like a word problem example please :)

9. Michele_Laino

namely?

10. anonymous

no just like a regular word problem

11. Michele_Laino

sorry, what is a regular word problem?

12. anonymous

just give me another example.. but as a word problem .. it doesnt matter what type @Michele_Laino

13. Michele_Laino

another example comes from drawings used to design architectural constructions

14. anonymous

thats not a word problem @Michele_Laino

15. Michele_Laino

I'm sorry, I don't know what is a word problem

16. anonymous

like this for example.. if the distance on a map is 2 cm represents 50 meters , what is the scale factor?

17. Michele_Laino

In that case, the scale factor is: $$2$$ cm corresponds to $$50$$ meters, or $$1:25$$

18. anonymous

ok now can you give me an example like that

19. Michele_Laino

another example, is from boats constructions: 600 millimeters represents a distance of 3 meters so the scale factor is: $$200:1$$

20. anonymous

ok thanks.. next question :) What are vertical angles? can you give an example?

21. anonymous

22. Michele_Laino

23. Michele_Laino

vertical angles is a couple of angles in which the sides of an angle are the prolongations of the sides of the other angle of the couple. Here is an example: |dw:1444060498908:dw|

24. anonymous

how do i explain that example to my teacher in words?

25. Michele_Laino

in that example we have considered the vertical angles which come from the intersection between two infinite coplanar and incident lines

26. anonymous

ok thanks :)

27. Michele_Laino

:)

28. anonymous

next!

29. anonymous

can you find the area and circumfrance of a circcle given the radius or diameter?

30. Michele_Laino

it is simple, if $$r$$ is the radius and $$D$$ is the diameter, then we can write this: $\begin{gathered} A = \pi {r^2} = \pi \frac{{{D^2}}}{4} \hfill \\ C = 2\pi r = \pi D \hfill \\ \end{gathered}$ $$A$$ stands for area, and $$C$$ stand for circumference length

31. anonymous

i dont understand

32. Michele_Laino

more explanation: $\begin{gathered} A = \pi {r^2},\quad {\text{ or }}A = \pi \frac{{{D^2}}}{4} \hfill \\ C = 2\pi r,\quad {\text{or }}C = \pi D \hfill \\ \end{gathered}$

33. anonymous

but i dont get any of those things... how would you explain it to a teacher. please make it very simple :) @Michele_Laino

34. Michele_Laino

here is the explanation using words only: area is given by the product of 3.14 by the square of radius

35. Michele_Laino

or by the product of 3.14 and the square of diameter divided by four

36. Michele_Laino

circumference is given by the product of 6.28 by the radius, or is given by the product of 3.14 by the diameter

37. anonymous

okay.. so is this the answer? area is given by the product of 3.14 by the square of radius or by the product of 3.14 and the square of diameter divided by four. circumference is given by the product of 6.28 by the radius, or is given by the product of 3.14 by the diameter.

38. Michele_Laino

correct!

39. anonymous

why did you use 3.14 and 6.28?

40. Michele_Laino

since, the quotient by the length of a circumference and the diameter of that circumference is an irrational number, namely: 3.14159....(infinite decimal figures) which can be approximated to 3.14

41. Michele_Laino

the quotient between*

42. Michele_Laino

6.28 is 3.14*2=6.28

43. anonymous

ok thanks :) next!

44. anonymous

can you describe the difference between complementary and supplementary angles?

45. Michele_Laino

complementary angles are angles whose sum is congruent to a right angle. here is an exmaple: |dw:1444061870759:dw| Supplementary angles are angles whose sum is congruent to a flat angle. here is an example: |dw:1444061943310:dw|

46. Michele_Laino

I meant AOB is a right angle* in the first picture

47. anonymous

next! :)

48. anonymous

can you discuss the differences between circumfrance and area of a circle?

49. Michele_Laino

area of a circle is the measure of the extension of that circle, whereas the circumference of a circle is the measure of the contour of that circle

50. anonymous

ok next! @Michele_Laino

51. anonymous

do you know what cross sections of a rectangular pryamid looks like? :)

52. Michele_Laino

if the cross section is made with a plane parallel to the base of that pyramid, then it is a rectangle

53. anonymous

ok but can you describe what it would look like in words :)

54. Michele_Laino

|dw:1444062444548:dw|

55. anonymous

ok thanks so much! please stay online because i have more questions for you :)

56. Michele_Laino

ok!:)