The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Learn more about arithmetic sequence here:
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x=2.7 x 10*-3
Step-by-step explanation:
-815x=2.24
x=-2.24/815
x=2.7 x 10*-3
Distance = sqrt [ (7.5 - -3.0)^2 + (-7.5 - .5)^2) ]
= sqrt 17,226.56 = 131.25 (answer)
Answer:
42
Step-by-step explanation:
Find the prime factorization of 126
126 = 2 × 3 × 3 × 7
Find the prime factorization of 420
420 = 2 × 2 × 3 × 5 × 7
To find the GCF, multiply all the prime factors common to both numbers:
Therefore, GCF = 2 × 3 × 7
GCF = 42
