Answer:the first one is 16 and the second one I don’t know and it’s kinda hard to see
Answer:
a) 325.72
Step-by-step explanation:
A=4pir^2
A=4x3,14x7.2x7.2
a=651.44
1/2a=1/2x651.44
=325.72
The 1st, 4th, and 7th terms make an arithmetic sequence of their own. The 4th term is the average of the 1st and 7th, so ...
(1st +7th)/2 = 4th
1st + 7th = 2×4th
1st = 2×4th - 7th
The first term is ...
2*141 - 132 = 150
