None because it is impossible for any triangle to have more than one obtuse angle.
We are told that the first term is 2. The next term is 7(2) = 14; the third term is 7(14) = 98. And so on. So, the first term and the common ratio (7) are known.
The nth term of this geometric series is a_n = 2(7)^(n-1).
Check: What is the first term? We expect it is 2. 2(7)^(1-1) = 2(1) = 2. Correct.
What is the third term? We expect it is 98. 2(7)^(3-1) = 2(7)^2 = 98. Right.<span />
Earth volume: (3/4).π.(6371)³ = 1,0832x10¹² km³
Pluto volume: (3/4).π.(1171)³ = 6,555,189,765 km³
How many spheres the size of Pluto does it take to have the same volume as earth?
volume Earth/ volume Pluto = 1,0832x10¹² / 6,555,189,765 = 165.25