As shown in the figure, equicircle ⊙ O1 and ⊙ O2 are circumscribed, and both are inscribed with ⊙ O. if the perimeter of ⊙ oo1o2 is 24cm, what is the radius of ⊙ o

As shown in the figure, equicircle ⊙ O1 and ⊙ O2 are circumscribed, and both are inscribed with ⊙ O. if the perimeter of ⊙ oo1o2 is 24cm, what is the radius of ⊙ o

The radius of ⊙ o is r, and the radius of ⊙ O1 and ⊙ O2 is r
2(R-r)+2r=24
R=12cm
The radius of O is 12 cm