Answer:
A = 7,241.2454026112 square mm.
or exact : A = 2,304.96*π sq mm
Step-by-step explanation:
Cylinder formula: A = π* r^2 + 2 *π * r* h + π*r^2
is the surface area.
d = 2r = 39.2 mm
h = 39.2 mm
r = 19.6 mm
A = π* r^2 + 2 *π * r* h + π*r^2
A = 2* π* (19.6)^2 + 2π (19.6)*(39.2)
A = 2,413.748467537 + 4,827.496935
A = 7,241.2454026112 square mm.
or
A = 2*pi* (768.32 + 384.16)
A = 2*1,152.48* pi
A = 2,304.96*π sq mm
Answer:
option A
Step-by-step explanation:
Answer:
We know that the equation of the circle in standard form is equal to <em>(x-h)² + (y-k)² = r²</em> where (h,k) is the center of the circle and r is the radius of the circle.
We have x² + y² + 8x + 22y + 37 = 0, let's get to the standard form :
1 - We first group terms with the same variable :
(x²+8x) + (y²+22y) + 37 = 0
2 - We then move the constant to the opposite side of the equation (don't forget to change the sign !)
(x²+8x) + (y²+22y) = - 37
3 - Do you recall the quadratic identities ? (a+b)² = a² + 2ab + b². Now that's what we are trying to find. We call this process <u><em>"completing the square"</em></u>.
x²+8x = (x²+8x + 4²) - 4² = (x+4)² - 4²
y²+22y = (y²+22y+11²)-11² = (y+11)²-11²
4 - We plug the new values inside our equation :
(x+4)² - 4² + (y+22)² - 11² = -37
(x+4)² + (y+22)² = -37+4²+11²
(x+4)²+(y+22)² = 100
5 - We re-write in standard form :
(x-(-4)²)² + (y - (-22))² = 10²
And now it is easy to identify h and k, h = -4 and k = - 22 and the radius r equal 10. You can now complete the sentence :)
