Answer:
r=3 ft
Step-by-step explanation:
it is similarity of two triangles
one
perpendicular side=10 ft
base=10/2=5 ft
second
perpendicular side=10-4=6 ft
Base r=?
Area is height time width, or in this case, 3(2x^2+3x+5), which is 6x^2+9x+15.
The 21st term of the given arithmetic sequence is 83. The nth term of an arithmetic sequence is applied to find the required value where n = 21.
<h3>What is the nth term of an arithmetic series?</h3>
The nth term of an arithmetic sequence is calculated by the formula
aₙ = a + (n - 1) · d
Here the first term is 'a' and the common difference is 'd'.
<h3>Calculation:</h3>
The given sequence is an arithmetic sequence.
3, 7, 11, 15, 19, ....
So, the first term in the sequence is a = 3 and the common difference between the terms of the given sequence is d = 7 - 3 = 4.
Thus, the required 21st term in the sequence is
a₂₁ = 3 + (21 - 1) × 4
⇒ a₂₁ = 3 + 20 × 4
⇒ a₂₁ = 3 + 80
∴ a₂₁ = 83
So, the 21st term in the given arithmetic sequence is 83.
Learn more about the arithmetic sequence here:
brainly.com/question/6561461
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Answer:
Step-by-step explanation:
Let the 
be the first number, 
be the second number and 
be the product of the first and second number.
i.e 
Now,
Hence,
Step-by-step explanation:
log <base a> b = x
means
a^x = b
So
3^2 = x^2+7x+21
x^2 + 7x + 21 - 9 = 0
x^2 + 7x + 12 = 0
(x+3)(x+4)
x = -3 or -4
