56 / 4 = 14
4 can go into 56 on 14 times...
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:
brainly.com/question/25749583
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Step-by-step explanation:
- 2x-2y=-6
3x+4y=8
multiply equation (1) by 3 and equation (2) by 2
- 6x-6y=18
6x+8y=16
Add
2y=34
y= 34÷2
y=17
substitute 17 for y in equation (2)
3x+4y=8
3x+4(17)=8
3x+68=8
3x=8-68
3x=-60
x=-60÷3
x=-20
x=-20,y=17
Answer:
0.034921 miles or 1843774 feet tall
Step-by-step explanation:
Using trigonometric functions we know that 
and 
where 
=angle and r is the hypotenuse of the triangle.
First we will calculate the hypotenuse using the x equation, since we know x = 1 mile (distance from the building on the ground) we have:
Now we will calculate the height of the building using the y equation and so:
The building is 0.034921 miles or approximately 184.3774 feet tall.
The first choice is substitution because G s being substituted by C
