A cylinder does not have diagonals in the same way that polygons do, as it is a three-dimensional shape. However, if you consider the line segments that can connect points on the curved surface and the two circular bases, you can think of the connections between points on the two bases. In a cylinder, you can connect points on the top base to points on the bottom base, but these are not classified as diagonals. Thus, the concept of diagonals is not applicable to a cylinder.
1188 of them.
Two
You don't - you need additional information. Many different rectangles can have the same diagonal. If you know the diagonal and one side (which must be LESS than the diagonal), you can use Pythagoras' Theorem to calculate the other side.
9 diagonals
A pentagon has 5 diagonals.
Parallelogram
A diagonal cannot be a side of a rectangle, and a side cannot be a diagonal.
There are four diagonal lines in a hexagon.
A heptagon has 4 diagonal lines and 7 sides and it has 2 congruent diagonal lines and 2 congruent triangles
1188 of them.
zero
it has 4 :)
4
14
It has one.
14.
Two