Answer:
r= 18
Step-by-step explanation:
use the Pythagorean theorem to solve this
[tex]r^{2} +24^{2} =(r+12)^{2}[/tex]
[tex]r^{2}+576=r^{2} +24r+144[/tex]
-144 -144
[tex]r^{2}+432=r^{2} +24r[/tex]
-[tex]r^{2}[/tex] -[tex]r^{2}[/tex]
[tex]432=24r[/tex]
/24 /24
18=r
