J.L. 3 years ago The figures below show two different ways of arranging four identical triangles of grey poster board on top of a white square. The square has sides equal to x + y, while the hypotenuse of each triangle is represented by the variable c. http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_1008_07/image0034e8ca1c0.jpg Hazel wrote the following statements to prove that c2 = x2 + y2.

1. J.L.

1. Area of the four grey triangles inside figure A = http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/1008/1008_G7_Q26a.gif 2. Area of the white square inside figure A = c2 3. Area of figure A = c2 + 2xy 4. Area of the four grey triangles inside figure B = http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/1008/1008_G7_Q26b.gif 5. Area of the two white squares inside figure B = 2x2+ 2y2 6. Area of figure B = 2x2+ 2y2 + 2xy 7. Area of figure A = area of Figure B, hence c2 + 2xy = 2x2+ 2y2 + 2xy 8. Therefore, c2 = x2+ y2 Which is the first incorrect statement in Hazel’s proof?

2. A.Avinash_Goutham

5 it's x2 + y2 i blive

3. gitahimart

its statement 8: in A: 4grey = 2xy 2white = c^2 therefore A = 2xy + c^2 in B: 2white: = 2x^2+2y^2 and area B = 2x^2+2y^2+2xy and if A=B, then 2xy + c^2 = 2x^2+2y^2+2xy c^2= 2x^2+2y^2, therefore statement 8 is wrong.

4. J.L.

These are my choices: Statement 5 Statement 6 Statement 7 Statement 4

5. J.L.

I thought it was statement 8 too but apparently its not

6. gitahimart

let me see, just a minute:

7. gitahimart

I get it since 1 and 4 are the same, then by same thinking then statement 5 should equal twice statement 2, hence 5 should read 2c^2 instead of 2x2+ 2y2, and hence 5 must be incorrect, what do you think?

8. J.L.

sounds good