Mans tools. Find his tooll for right angles 90* draw this on paper or cardboard and then fold in half.
Children raid their maths equipment and find peetractor and draw your lines , geometry at school.
Remember do you have any ruler if so the corner of any ruler is 90 and a diagonal line through each square is 45.
Hope this makes sense. Does to me but I love maths. Just thought look on computer how to make these angles should get some school papers on this subject.