Which types of triangles can be formed by taking the cross-section of a cube?

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?