* PLEASE ANSWER TY! *

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the Concept of the Circles.
thus the, Equation of circle with centres as (h, k) is given as,
(y-k)^2 + (x-h) ^2 = r^2
where, r is the radius if the circle.
so here, we can see that,
[tex] {r}^{2} = 100 \\ r = 10 \\ [/tex]
thus , we can say that, 2r = d
thus diameter = 20 units