The middle section is n(n+1)
The top row is n+2
The bottom row is 2n+1
So the rule for the total number of tiles will be the sum of the above rules...
s(n)=n(n+1)+n+2+2n+1
s(n)=n^2+n+n+2+2n+1
s(n)=n^2+4n+3
-9-(-12)=-9+12=3
-9-12=-9+(-12)=-21
We know that
a1=1
a2=3
a3=9
a2/a1=3/1----> 3
a3/a2=9/3----> 3
<span>common ration r is equal to 3
number of terms n is 12
The </span><span>Sum of geometric series is given by the formula
</span>Sum=a1*[1-r<span>^n]/[1-r]
</span>Sum=1*[1-3^12]/[1-3]-----> Sum=[1-3^12]/[1-3]----> [3^12-1]/[3-1]
<span>Sum=531440/2-----> 265720
the answer is
265720
</span>
Answer:
B. feet/second
Step-by-step explanation:
