ANSWER
a. d+4
b. 4d+16
EXPLANATION
The area of the square coaster is represented by:

We split the middle term to obtain,

We factor by grouping to get,


Since area of a square is l² , it means the side length of the square is

b) The perimeter of a square is given by

We substitute the length in terms of d, to obtain;

Or

Answer:
option A
Step-by-step explanation:
Notice that you need to emulate the series: 1 + 5 + 25 + 125 + 625 (a five total term series)
with the indicated sums.
The first term in the your series (addition) has to be "1". This fact already gets rid of two of the suggested sums (B, and D) because their first term is
.
So, now analyzing the options A and C, we notice that A has a sum from i=0 to 4 (which gives a total of five terms ao, a1, a2, a3, and a4, while option C has a total of six terms (from i = 0 to 5): a0, a1, a2, a3, a4, a5.
S, the obvious candidate is option A. So now evaluate the five terms corroborating that:

Therefore, option A is the answer
Aritmetic increases by the same number
geometric has 1 number that each term is multiplied by to get the next term
4 to 9 is 5
9 to 13 is 4
not same difference
9/4=13/9?
81/36=52/36?
no
neither aritmetic nor geometric
The length of BC is 72 I hope this will help uh