Help with Year 5 Maths homework

[LittleCabbage]

DC has been given this question. Am I right in thinking they have not been given enough of the measurements to calculate this? Surely the top and bottom "arms" of the cross cannot be assumed to have the same 22m and 30m measurements that the left and right arms have, just because there are vertical and horizontal lines of symmetry?

Or is my maths totally off?

As an example, this shape has vertical and horizontal lines of symmetry, but does not have the same measurements for each arm:

Yeah I understand where 4 of your 30s and one 22 come from but you are assuming 4 30s and 2 22s just because they look the same. The 7s are correct. They would need diagonal lines of symmetry too for your DC to be correct.

I meant 3 30s. One of the 4 was already given.

You’re overthinking it.
They are assuming you look at the diagram and see that it’s symmetrical and the measurements are all the same.

Yes technically they should specify it’s diagonally symmetrical too but it’s year 5 homework, don’t overthink it.

I agree, and I think you've very clearly demonstrated it with your example.

I suspect the teacher would mark "not enough information given" as wrong though .

It's a lack of care and exactness in posing the problem. It's easily done, but it's a mistake better avoided in maths.

Thanks all. Glad it isn't just me! I won't flag it up to the teacher but will explain to DC why they should have been given more info.

I disagree that I am overthinking it. Maths should encourage critical thinking, and this question is encouraging making false assumptions!

Yes, you’re right actually. This is a twinkl resource by the looks of it, and they usually respond quickly and update things if you point out mistakes, so actually in this instance I would mention it to the teacher so they can feedback to twinkl. It’s a paid for resource so mistakes like this should be corrected.

It doesn't say Twinkl anywhere on the sheet, but maybe was lifted from there?

I recognise the font! It’s easy to trim off the twinkl logo if you don’t want it on there.

Perhaps I will mention it to the teacher then, hmmm.

I have just looked at it on Twinkl and it has more info provided on the question than you have there. There is a 30m on the bottom left vertical line and a 22m on the bottom horizontal line.

@Noodledoodledoo

I have just looked at it on Twinkl and it has more info provided on the question than you have there. There is a 30m on the bottom left vertical line and a 22m on the bottom horizontal line.

Oh, how strange! I guess Twinkl has been updated but DC's teacher has an old copy stored away that they just keep photocopying.