Answer:
its octagon. first and last one it has total 8 sides
0.380952 then the numbers repeat
X/12=(2 1/3)/5 note that 2 1/3=7/3
x/12=(7/3)/5
x/12=7/15 multiply both sides by 12
x=84/15
x=28/5
x=56/10
x=5.6
This problem is an example of an arithmetic series.
The common difference of the second term (15) with the first term (9) and the third term (21) with the second term (15) [15-9=6; 21-15=6] is 6.
The formula for solving this is:
An= A1 +(n-1)*d where An is the nth term, A1 is the first term, n is the number of terms and d is the common difference.
An=9+ (31-1)*6 = 189
The answer is 189.
Angle B corresponds to ANGLE E.
You can simply tell by looking at the letters that are arranged.
ΔA<u>B</u>C = ΔD<u>E</u>F
Hope this helps
