The first answer is “B” and the second one is “D”. Attached below is my work.
I hoped this helped!! ^w^
Xi = Xi-1 * 30
So X12 = X1 * 30^11
Which is huge, should be A
It actually looks like y= xsquared to me
Yes, all 6 digit numbers have 6 addends in their expansion
I believe you are looking for the surface area.
Keep in mind B is the area of the base.
SA = LA + 2B
LA = HP
SA= HP + 2B
SA = 7.21 * 8 + 32
SA = 57.68 + 32
SA = 89.68 unit squared