If area is 81pi then 81pi=pir^2. Divide both sides by pi and we are left with r^2=81 take the square root of both sides to find the radius is 9 then plug that into the equation for circumference(2pir) so 2pi(9)=18 pi so the answer is E 18pi
Answer:
x = (y - 4)/7
Step-by-step explanation:
Subtract 4 from both sides to get:
y - 4 = 7x
Then, divide both sides by 7 to get:
(y - 4)/7 = x
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hello :<span>
<span>an equation of the circle Center at the
A(a,b) and ridus : r is :
(x-a)² +(y-b)² = r²
in this exercice : a =4 and b = -1 (Center at the origin)
r = AP.... P(0.1)
r² = (AP)²
r² = (4-0)² +(-1-1)² = 16+4=20
an equation of the circle that satisfies the stated conditions.
Center at A(4,-1), passing through P(0, 1) is : </span></span>(x-4)² +(y+1)² = 20
