Answer:
radius = 4
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
(x - 2)² + (y - 8)² = 16 ← is in standard form
with r = [tex]\sqrt{16}[/tex] = 4
