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# Am I going mad? watch

1. Ok, so I want to calculate the area of this rectangle. The width is sqrt(10), the length is 5. Area is 5sqrt(5). That's basic Pythagoras. But then the solution bank calculates the area of the two triangles. The area of both can be calculated by 0.5 * 5 * 3. Add them together and you get 15, a slightly smaller figure than with the other method. Wtf is going on? It's exercise 4I q3 part c of the edexcel fp1 book.
2. (Original post by jpepsred)

Ok, so I want to calculate the area of this rectangle. The width is sqrt(10), the length is 5. Area is 5sqrt(5). That's basic Pythagoras. But then the solution bank calculates the area of the two triangles. The area of both can be calculated by 0.5 * 5 * 3. Add them together and you get 15, a slightly smaller figure than with the other method. Wtf is going on? It's exercise 4I q3 part c of the edexcel fp1 book.

It is not a rectangle.
3. (Original post by 16Characters....)
It is not a rectangle.
It has two sets of parallel sides, so it is at least a parallelogram. And the book describes it as a rectangle.
4. (Original post by jpepsred)

Ok, so I want to calculate the area of this rectangle. The width is sqrt(10), the length is 5. Area is 5sqrt(5). That's basic Pythagoras. But then the solution bank calculates the area of the two triangles. The area of both can be calculated by 0.5 * 5 * 3. Add them together and you get 15, a slightly smaller figure than with the other method. Wtf is going on? It's exercise 4I q3 part c of the edexcel fp1 book.
Check again... it's not a rectangle.
5. (Original post by jpepsred)
It has two sets of parallel sides, so it is at least a parallelogram. And the book describes it as a rectangle.
It describes it as a rectangle? Huh, you are right it has two sets of parallel sides but the adjacent sides are not perpendicular so it is a parallelogram not a rectangle.
6. (Original post by 16Characters....)
It describes it as a rectangle? Huh, you are right it has two sets of parallel sides but the adjacent sides are not perpendicular so it is a parallelogram not a rectangle.
You have no idea how mad this made me. I'm just relieved that I am in fact sane, and not completely incompetent at maths.
7. (Original post by jpepsred)
You have no idea how mad this made me. I'm just relieved that I am in fact sane, and not completely incompetent at maths.
No I can well imagine your pain, my exam board's (MEI) textbooks are full of mistakes and I regularly end up in situations like this. Though this would be a new low even for MEI!
8. (Original post by 16Characters....)
No I can well imagine your pain, my exam board's (MEI) textbooks are full of mistakes and I regularly end up in situations like this. Though this would be a new low even for MEI!
You should get your teachers to map out a list of corrections for past erroneous entries.Imagine the financial stress of building so many more mental institutions because of students going mad over math. Peace.

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