## anonymous one year ago the diameter of circle symbol z is 5 in. what is the area in terms of pi ?

1. anonymous

2. Nnesha

what's the formula to find AREA of a circle ??

3. anonymous

4. Nnesha

yes right and diameter is half of radius you can use this formula to find radius $\huge\rm r=\frac{ d }{ 2 }$

5. anonymous

so 2.5 in squared ?

6. Nnesha

yes right take square of 2.5

7. anonymous

huh?

8. Nnesha

well radius is 2.5 right ?

9. anonymous

yes it is

10. Nnesha

$\huge\rm A =\pi r^2$

11. Nnesha

substitute r for 2.5 ^^

12. anonymous

ok i get 6.25

13. Nnesha

right

14. Nnesha

and we have to write it interms of pi

15. anonymous

ok so 6.25pi in squared

16. anonymous

can you help me with another one @Nnesha

17. Nnesha

i willlll try not sure:=)

18. anonymous

can you help @DanJS

19. DanJS

ok

20. anonymous

21. anonymous

this is the question

22. DanJS

the point C(x,y) is 3/4 the way from A to B along a line... youc an set up 2 equations involving x and y and solve or...

23. DanJS

since it is a line with a constant slope , the x and y components of that form a right triangle realizing that the relation between the lengths of each side by the pythagorean theorem c^2 = a^2 + b^2 if you shrink the hypotenuse down by 3/4 you have to do that to the other terms too

24. DanJS

(3/4)c^2 = (3/4)*a^2 + (3/4)*b^2

25. anonymous

ok

26. DanJS

so you can just look and see the change in x coordinate, and find 3/4 that, and add that to the start value

27. DanJS

Same for y coordinate

28. anonymous

ok so how do i this then ?

29. DanJS

The length in the x direction from A to B is 16, 3/4 of that is 12 start at A and move 12 in the X direction, that is the x coordinate of C

30. DanJS

do the same for the Y direction

31. anonymous

so 2,0

32. anonymous

thats what i got

33. DanJS

yeah, sounds good

34. DanJS

It is just basically shrinking a right triangle by 25% then seeing where it lies on the coordinates

35. anonymous

so i got that right ?

36. DanJS

or you can do it by setting up 2 equations involving x and y in the point N, then solving for the x and y

37. DanJS

Distance AC = 3/4 * Distance AB and equation of the line through AB

38. anonymous

ok cool but am i right ?

39. DanJS

yes, you can check by just calculating the distances AB and AC and check if they are correct