It's too easy this way; usually they just give us the radius and we go from there.
This is 10 triangles with height 5 and base 3.25

Answer: 81.3
Answer:
13/19, since we are in a pattern in which the number is added by 2/19 each time 11/19+2/19 would equal to 13/19
I think it is (10-x)=x pls correct me if I’m wrong
5.22875816993
Hope this helps
I think that you have to divide.