Answer:
2 units
Step-by-step explanation:
The given equation of the circle is:
[tex]x^{2} + y^{2}+8x-6y+21=0[/tex]
The general equation of the circle is:
[tex]x^{2} + y^{2}+2gx+2fy+c=0[/tex]
Comparing the given equation with the general equation we can say:
g = 4
f = -3
c = 21
The formula for radius of the circle is:
[tex]radius=\sqrt{g^{2} +f^{2} -c }[/tex]
Using these values of the given circle, we get:
[tex]radius=\sqrt{(4)^{2}+(-3)^{2}-21}\\\\radius=\sqrt{4}\\\\radius=2[/tex]
Therefore, the length of radius of the given circle is 2.
