TMUA Question help

Why can't it be all three? Why can't 1 line work.1 line in my diagram literally works. It is a straight line to give 2 triangles. Assume this is an obtuse angle.

It would probably be clearer to draw triangles which are more acute/obtuse, rather than something which is almost right. But assuming the top angle is > 90, then you have drawn the obvious altitude, but you could put two other lines on there that divide the obtuse angle into 90+acute and acute+90 and youd have 3 distinct lines.

But why do I need these 2 other lines? This makes 0 sense. You have 1 line, it makes 2 right angles, which is sufficient for the "1 straight line", why do i HAVE to have 2 other lines?
What is an altitude? This isn't on the TMUA spec.

i managed to get 1,2 & 3 lines:
i) for 1 line use an isosceles triangle
ii) for 3 lines use an equilateral triangle
iii) for 2 lines use an obtuse triangle

Just as well youre not taking the tmua :-). The answers is always 3 when the original triangle is not right.

The question says exactly one, two or three. The answer is that there are always 3 lines which give at least one right angled triangle. So if there are 3 lines, then if you just draw one of them, it does not mean there are exactly one. There are exactly 3.
So if the triangle is acute, you can draw 3 lines, starting at each vertex and meeting the opposite side at a/two right angle, so each line produces two right triangles. Theyre called altitudes. Its just a name.
If your triangle is obtuse, you can draw one line starting at the obtuse vertex and meeting the opposite side at a/two right angles as before. However, you could also draw two other lines which start at the opposite side and divide the obtuse angle into 90+acute and acute+90, each producing one right triangle. So there are exactly 3 such lines.

but what is telling us that we need to have the other 2. 1 line works enough to be sufficient. is there anything blocking the requirement of 2 other lines that NEED to be there? I am really confused

The question asks for how many lines there are, and there are exactly 3, as described in the previous post.
If you just draw 1, the other 2 still exist. Youve just not drawn them.

I really am confused. I really can't understand why 3 is required or why I need to have the other 2. I'm not wrong for thinking if I drew one line I meet the criteria, but I don't understand why I need to draw 3 lines

Without being funny, do you understand why an acute angle can be divided by 3 lines (altitudes) as in the previous post?
Do you understand why an obtuse triangle can be divided by 1 altitude (the line you drew) and 2 other lines, both of which start at the side opposite the obtuse angle and they split the obtuse angle into a right angle + an acute angle? Again as described in the previous post.
Its not about need or required or ... Each triangle can be divided by 3 such lines.

I understand that 3 lines work. I do not understand why 1 or 2 lines don't work. Why do I have to divide by 3 total lines.

There are exactly 3 such lines. There is not exactly 1 line as there are 3.

ok but you are not explaining to me why there are 3 lines only.
Their mark scheme really confuses me because it both contradicts what your saying that obtuse has 1 line yet has 3?