Answer:
S
ThenSn=n(a1+an)2Sn=n(a1 + an)2 , where nn is the number of terms, a1a1 is the first term and anan is the last term. The sum of the first nn terms of an arithmetic sequence is called an arithmetic series .
Step-by-step explanation:
Answer:
The answer is 131
Step-by-step explanation:
This is ed right? If so the answer would be c
9514 1404 393
Answer:
(c) ∠ECF and ∠BCF
Step-by-step explanation:
Complementary angles total 90°. Here, 90° angle BCE is divided by ray CF into two complementary angles. They necessarily have a total of 90°.
∠ECF and ∠BCF
.3 = 3/10
.5 = 1/2
.05 = 1/20
.25 = 1/4