Answer:
Step-by-step explanation:
You know how subtraction is the <em>opposite of addition </em>and division is the <em>opposite of multiplication</em>? A logarithm is the <em>opposite of an exponent</em>. You know how you can rewrite the equation 3 + 2 = 5 as 5 - 3 = 2, or the equation 3 × 2 = 6 as 6 ÷ 3 = 2? This is really useful when one of those numbers on the left is unknown. 3 + _ = 8 can be rewritten as 8 - 3 = _, 4 × _ = 12 can be rewritten as 12 ÷ 4 = _. We get all our knowns on one side and our unknown by itself on the other, and the rest is computation.
We know that 
; as a logarithm, the <em>exponent</em> gets moved to its own side of the equation, and we write the equation like this: 
, which you read as "the logarithm base 3 of 9 is 2." You could also read it as "the power you need to raise 3 to to get 9 is 2."
One historical quirk: because we use the decimal system, it's assumed that an expression like 
uses <em>base 10</em>, and you'd interpret it as "What power do I raise 10 to to get 1000?"
The expression 
means "the power you need to raise 10 to to get 100 is x," or, rearranging: "10 to the x is equal to 100," which in symbols is .
(If we wanted to, we could also solve this: 
, so 
)
Answer:
Step-by-step explanation:
The formula for determining the the area of a sector is expressed as
Area of Sector = θ/360 × πr²
Where
θ represents the central angle.
π is a constant whose value is 3.14
r represents the radius of the circle.
From the information given,
The central angle is π/7 radian. Converting to degrees, it becomes
π/7 × 180/π = 180/7 = 25.714 degrees.
Area of sector = 77 square meters
Therefore
77 = 25.714/360 × 3.14 × r²
77 = 0.2243r²
r² = 77/0.2243 = 343.29
r = √343.29 = 18.53 meters
