(Statistics) Fill in the blank & explain

it would open into a square depending on the type of envelope i’m not sure about the second part

for this case we have that by definition, the surface area of a cylinder is given by:

where:

r: it is the radius of the cylinder

h: it is the height of the cylinder

we can also rewrite it as:

where:

la: it's the lateral area

ba: area of the base

option a

55 degrees because 55+55=110 degrees