For those not wanting to click, there are two questions.

1. What is the length of x?

2. Can you:

i) Divide a square into five rectangles such that no two rectangles share an entire side in common – i.e. the sides of abutting rectangles never start and finish at the same points? (The rectangles do not need to be the same size or shape.)

ii) Divide an 11 x 11 square into five rectangles in such a way that the ten side lengths are the whole numbers from 1 to 10? Hint: if you have solved part i) use this arrangement of rectangles.

I find the triangle problem a bit silly. There's a clever insight to easily solve it, but the alternative, systematic approach is not exactly high-level knowledge.