Answer:
r=3
Step-by-step explanation:
24π=2π(r^2+r)
Divide each side by 2 pi
24π/2π =2π/2π(r^2+r)
12 = r^2 +r
Subtract 12 from each side
12-12 = r^2 +r -12
0 = r^2 +r -12
Factor
What number multiply to -12 and add to 1
4*-3 = -12
4-3 = 1
0= (r+4) (r-3)
Using the zero product property
r+4 =0 r-3 =0
r+4-4 =0-4 r-3+3=0+3
r = -4 r = -3
Assuming r is the radius, r must be positive
r =3
