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| Thread ID: 100186 | 2009-05-29 06:12:00 | Working out the area of a quadrilateral | Jen (38) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 777880 | 2009-05-29 06:12:00 | Hi all, A challenge for the mathematically minded! I need to find out the surface area (m2) of my pergola roof. Unfortunately, the roof is a weird shape and my poor brain cannot work the maths out. :waughh: Can anyone please work it out for me? I've attached a drawing indicating the lengths (in metres) of each side. Thanks. :) |
Jen (38) | ||
| 777881 | 2009-05-29 06:28:00 | My guess is about 15 square metres! Wonder how close I will be when the maths whiz kids arrive. :thumbs: | Richard (739) | ||
| 777882 | 2009-05-29 06:29:00 | You could cut it into two triangles and one rectangle. Will try to work it out when I'm not so sleepy anymore. :lol: | qazwsxokmijn (102) | ||
| 777883 | 2009-05-29 06:34:00 | If I remember my high school maths correctly, then this will probably require simultaneous equations. | somebody (208) | ||
| 777884 | 2009-05-29 06:40:00 | Need angles or more lengths. Also, png is your friend. |
roddy_boy (4115) | ||
| 777885 | 2009-05-29 06:43:00 | It's not easy - I haven't been to school recently!! As far as I can work it out, if you square up everything by extending the lines to the points of intersection, you end up with a rectangle that is 5m x 4.35m (21.75m sq). Then you can work out the area of the top triangle (2.75m x 5m /2 = 6.875m sq) But I'm stumped on the area for the triangle on the right - no right angle in that one. Come on, who's recently passed NCEA Maths!! (Or can remember School C maths) |
johcar (6283) | ||
| 777886 | 2009-05-29 06:44:00 | Draw a line between any two opposite corners, find the area of the two triangles. (If you draw your line from top left to bottom right, you have one right angled triangle. it is real easy to find the hypotenuse of those widgets, and the unknown side of the other triangle is likely quite similar.) | R2x1 (4628) | ||
| 777887 | 2009-05-29 06:49:00 | I just drew it up in AutoCAD. The area is 13.611 sq.m. | seltsam (13470) | ||
| 777888 | 2009-05-29 06:52:00 | I just drew it up in AutoCAD. The area is 13.611 sq.m.Good thinking! Thanks for that. :thumbs: Thanks to everyone else who contributed ideas. :) |
Jen (38) | ||
| 777889 | 2009-05-29 06:56:00 | Make it into a rectangle, then use a2 + b2 = c2 to find the area of the added bits. Use wxh to find total area Take a way area of added bits = answer |
jwil1 (65) | ||
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