PSLE - New Format for Maths

[david59]

leungyc:

pinky88:

[quote]
How is it possible to have the slop same length as the side (the centre line has a \"cut\" indicating same length as the other two lines.

The centre line is from the edge of the square to the other edge. So it's possible.

If the 3 lines are of the same length, then the angle of the intersecting chord cannot be 90 degree. you can do a mathematical proof that this angle will not be 90 degree, if the 3 lines of the triangle are of same length[/quote]The centre line which is equal to the two slanted lines is measured from the top to the bottom of the diamond. I think some students misunderstand the symbol to mean from the point of the cross section to the bottom of the diamond which would certainly make it impossible to draw the diagram.

[Joy]

Hi


Can i check with you , is there any other information given besides the diagram?thanks

rgds

kohjl:

ilaks:

Hi all,

here is how the image looked like for the geometry question (to best of my child's knowledge)

Not drawn to actual size. Answer was 150

http://www.postimage.org/

Thanks for sharing this question. Were any other dimensions given, like the sides of the rectangle, etc?

[CrazyDad]

I think any number between 90 degree and 179 degree will be considered correct. By drawing a semi circle, draw any two lines from the centre of the circle to the edge of the circle. Then draw another line right in the middle of the two. Any diagram drawn under the above condition fits the question, unless something is missing. So I believe fee point will be awarded to all students.



or just day dreaming :idea:

[Joy]

I also think so cos the info is inadequate.

CrazyDad:

I think any number between 90 degree and 179 degree will be considered correct. By drawing a semi circle, draw any two lines from the centre of the circle to the edge of the circle. Then draw another line right in the middle of the two. Any diagram drawn under the above condition fits the question, unless something is missing. So I believe fee point will be awarded to all students.


or just day dreaming :idea:

[turquoise]

The answer is 150 deg. The easiest way to get the answer is via the equilateral triangle and isosceles triangle method. Several posters have already shown how to derive the answer.


If still in doubt, draw the figure on a piece of paper, making sure you have a square, and the three lines are of the same length. Measure the angle. It’s 150 deg.

[chochipkooky]

Does anyone know whether it was clearly shown that the 4 sides were of equal length thus making it a square? If not, I agree with CrazyDad. Information inadequate.

[turquoise]

chochipkooky:

Does anyone know whether it was clearly shown that the 4 sides were of equal length thus making it a square? If not, I agree with CrazyDad. Information inadequate.

It's stated in the question.

[James Ang]

chochipkooky:

Does anyone know whether it was clearly shown that the 4 sides were of equal length thus making it a square? If not, I agree with CrazyDad. Information inadequate.

Yes, it is a square and the information is provided that it is a square as my students have told me. That means all the 3 equal lines are the radii of the arc (incomplete circle) and that makes all the 3 lines (length of square) and all the 3 radii equal and thus the equilateral triangle.

[chochipkooky]

Ok, then. 150 degrees should be the right answer. My son got it wrong.

[justsay]

http://www.postimage.org/



Is this the exact drawing appear in the question paper ? My daughter remembered the middle line appeared to be dotted and she and her classmate said that they were quite sure there wasn't a '-' in the middle to show that those are isoceles triangles ? :?