"My students, ahh. Textbooks. They say, 'My pretty little students, here's a formula! I will give you numbers and you plug it in.' Then he would say, 'I don't like textbooks. I'm a rebel! So, I derive the formula.'"
He made us derive it. But the formula is this: 1/2 x b x h. Why? The real formula is because two equal triangles are both HALF of a PARALLELOGRAM.
Parallelogram area formula is b x h, or base x height. So half of that? (b x h) / 2, or 1/2 x b x h.
Plug this in.
Assuming your triangle is equilateral, I plug in 2.5 for the base and 8.75 for the height.
It is a strangely worded question but you are dividing the paper in 3's n times so 3n will be part of the answer and you are dividing 200. So, the answer is 200/3n.