## anonymous one year ago I cannot figure out how to calculate the area of this irregular figure and I could use some help. Thanks!

1. anonymous

2. nikato

i think i would divide it into two trapezoids. one on top and other on bottom

3. anonymous

Any idea how I can figure out the lengths of each side? I'm fairly stumped on that

4. mathstudent55

I agree. Use a horizontal line to divide the figure into two trapezoids. You need to make a few assumptions, if you were not told this info specifically. The bottom right angle must be a right angle. The two side endpoints in the middle of the right and left sides must be at the same height.

5. nikato

|dw:1433972764485:dw|

6. anonymous

How do we know that the two points coming off the right angle are the same height?

7. nikato

|dw:1433972877965:dw| you're two trapezoids

8. nikato

|dw:1433972904320:dw|

9. nikato

|dw:1433972929542:dw|

10. anonymous

260-15- is 110, so the height of the top trpaezoid is 110. and that means the bottom ones hjeight must be 150.

11. nikato

yup

12. ganeshie8

|dw:1433972798403:dw|

13. anonymous

Then we get 110*195?

14. anonymous

for the top trapezoid

15. mathstudent55

@ganeshie8 I don't understand your question. The figure clearly shows that the maximum width of the polygon is 265 ft. How can you move the vertex on the left and make it narrower than 265 ft?

16. nikato

^I agree. and to find area of trapezoid (sum of bases/2) x height so the top would be [(125+265)/2]x 110

17. anonymous

THis is what I am putting down for the top, am I correct? We know the top is 110 high (260-150), and then we do A=110*((265+125)/2 which adds up to 21450 square feet in the top trapezoid.

18. anonymous

Ignore the missing parenthesis

19. nikato

yes. i got that for the top one too

20. ganeshie8

Ahh so it doesn't matter where the left most vertex moves on the vertical line |dw:1433973606686:dw|

21. anonymous

Awesome. SO now all we have left is the bottom?

22. ganeshie8

(for area)

23. anonymous

ANd we know the hegiht is 15, the base is 15, and the lid is 265

24. anonymous

Right?

25. anonymous

26. mathstudent55

Read my comment way above. We need to make two assumptions for this problem to be solvable with the info we are given.

27. anonymous

Ya, I have to assume 150 for the sides

28. mathstudent55

|dw:1433973761953:dw|

29. nikato

yes. that is true. now plug those numbers into the formula to find area. also if we dont assume these things, i dont think we have enough info

30. ganeshie8

`The two side endpoints in the middle of the right and left sides must be at the same height.` this assumption is also not required right ?

31. mathstudent55

If you do not make that assumption, you may not have two trapezoids.

32. ganeshie8

doesn't matter, area wont change

33. mathstudent55

We also need to assume that the top side and the bottom side are parallel to each other and parallel to the mid segment.

34. mathstudent55

The area won;t change, but how will you calculate it if we do not deal with trapezoids?

35. ganeshie8

that is a different problem haha

36. anonymous

@ganeshie8, are you saying I have the wrong question?

37. mathstudent55

@ganeshie8 Right. BTW, how do you copy a figure into the draw tool, and how do you edit it in color like you did above?

38. ganeshie8

nope, im still trying to convince myself that the actuall question is valid as it stands

39. nikato

the bottom looks right. now just add the two areas together and you have solved your problem based on a lot of assumptions then

40. anonymous

Whether or not the question is valid, I gotta write in something. I have 2 days to go before the simester ends and everything closes up, and since I got hit by a car on the 12th last month, I am behind around a week at this point.

41. anonymous

To solve this, we cut the top into a trapezoid and the bottom into a trapezoid. We know the top is 110 high (260-150), and then we do A=110*((265+125)/2) which adds up to 21450 square feet in the top trapezoid. Bottom trapezoid has a base of 150, a height of 150, and a lid with a length of 265. 31125=150*((265+150)/2) Is this correct? Assuming we made all the agreed on assumptions that have to be done.

42. anonymous

I think I have an answer, can I beg one of you to check it?

43. nikato

yea. that looks right. but i dont know why you call it a lid, instead of just the other base. and dont forget your last step, to add both the areas

44. anonymous

Alright, thanks man.

45. anonymous

I really do appreciate all your guys help. I was lost on this one.

46. anonymous

I have another account if one of you guys wants another medal

47. ganeshie8

Never do that. Medal the person that helps you most.

48. anonymous

Youall helped me a ton. I gave the medal to Nikato, but thank you all.

49. mathstudent55

You're welcome.

50. anonymous

Should I close it, or did you guys want to continue talking?

51. ganeshie8

It is okay to close as soon as you're done because you can't open a new question w/o closing the present q

52. anonymous

Alright.