Thank you so much friend.
I think a advantage of this will be that we will be able to tell our grandchildren about how we survived the pandemic, just like our grandparents talk about World War. Lol.
Answer:
k - 11
Step-by-step explanation:
Answer:
4th option (sqrt(10))/2
Step-by-step explanation:

S1 = 72
S2 = 12 = 72*(1/6)
S3 = 2 = 72*(1/6)^2
.
.
.
S15 = 72*(1/6)^14 = 9.18*10^(-10)
Cosine is the ratio of the adjacent side to the hypotenuse.
In short, we have this equation
cos(angle) = adjacent/hypotenuse
In the case of cos(A) = 18/19.5 we can see that
adjacent = 18
hypotenuse = 19.5
The side of 18 cm is next to angle 2, so the 18 cm side is adjacent to angle 2 (in contrast, the 7.5 cm side is the opposite leg in relation to angle 2)
So that's why the answer is angle 2
In other words, replace the '2' angle marker with 'A' to be able to write cos(A) = 18/19.5