Answer:
The 1st term is -67
Step-by-step explanation:
I. When Sn =
(
)
If Sn = 124, n = 8 and
= 98
124 = 8/2(a + 98)
124 = 4(a + 98)
124 = 4a + 392
124 - 392 = 4a
-268/4 = a
-67 = 
Hope that help :D
4 + 12 +12 = 28cm
so in conclusion it is 28
Ok so... what wait weres the pic??
11.2 x 11 x 8 is 985.6
so uh- yeah i hope that helped lol