St Albans High School for Girls maths question

[PurpleDuck]

'chose whichever line of symmetry you like and then shade in three squares to make the pattern symmetrical'

The problem is that the three squares bit means that one diagonal line is not enough to work. You need two diagonal lines, so the "any line" is more than one line.

Now am completely lost - why would 3 squares not work with one diagonal? If I mark the little squares A-E and 1-5 (left-right and top-bottom) and shade in A3, C5 and E3, I get a symmetrical pattern whichever diagonal I use as a line of symmetry, but only using one diagonal at a time. It is not symmetrical using two diagonals simultaneously. That's what I meant by saying 'choose whichever line of symmetry you want and then shade in 3 squares' (which may not be what the question asks for).

[Proud_Dad]

If you only choose one diagonal you would only need to shade one square to make it symmetrical.

i.e. If you choose bottom left to top right you just need to shade A3.
If you choose top left to bottom right you just need to shade E3.

Shading A3, E3 and C5 WOULD make it symmetrical about both diagonals simultaneously but that's not what the question asks. It says any line and nothing about diagonals.

[ontarget]

You're right. I am getting confused, looking at it for too long.

[ontarget]

Proud_Dad is right, if you chose the left diagonal, there would be no need to shade E3 and C5

[Guest55]

This is not the only poorly worded questions imho and the quality of several diagrams - the temperature scale and the angle questions - is extremely disappointing.

[PurpleDuck]

Proud_Dad is right, if you chose the left diagonal, there would be no need to shade E3 and C5

Yes, I agree one square would be enough but I shaded three squares, because the question said we needed to shade three. I think we all have been looking at it too long!

[Proud_Dad]

This is not the only poorly worded questions imho and the quality of several diagrams - the temperature scale and the angle questions - is extremely disappointing.

What do you think's wrong with the temperature and angle questions (which question numbers do you mean?). I thought those ones looked OK?

[Guest55]

Q11, Q24 and Q27 have very poor quality diagrams - the rectangle does not even look like one!

Another example of poor wording is Q13 - 25% is a percentage not really a ' number'.

[PurpleDuck]

Shading A3, E3 and C5 WOULD make it symmetrical about both diagonals simultaneously but that's not what the question asks. It says any line and nothing about diagonals.

That's right, it does not say anything about diagonals, but diagonals are the only lines that would work with 3 more shaded squares. With a vertical line of symmetry, one would need to shade in a minimum of 4 squares and with a horizontal one, five squares would be needed to get a symmetrical pattern.

When I thought of a 'simultaneous' symmetry with two diagonals, for some reason I assumed the pattern would have needed to have four quarters looking the same, but, on reflection, that's probably not required in which case shading A3, E3 and C5 would make it symmetrical with two diagonals simultaneously, just as you said.

[Proud_Dad]

Q11, Q24 and Q27 have very poor quality diagrams - the rectangle does not even look like one!

Another example of poor wording is Q13 - 25% is a percentage not really a ' number'.

I agree that 25% isn't a number and that's bad wording.

I personally don't think there's anything wrong with the 3 diagrams though. The thermometers have legible scales which is all that's needed in order to draw a line in the right place.

The rectangle does look a bit wonky but I think maybe that's deliberate. (It even states diagram not to scale underneath). If the diagram was perfect they could just measure the angle with a protractor, but that's not the point of the question. Whatever it looks like on paper it IS a rectangle in theory because it is shown having 2 opposite right angles, and perhaps that's what they're getting at?

Same with Q24. b = 2c because it says it is!