Answer:
option 2: 15
Step-by-step explanation:
ΔBOA is a right angled triangle.
By Pythagoras theorem,
[tex] {oa}^{2} = {bo}^{2} + {ba}^{2} [/tex]
[tex] {oa}^{2} = { {9}^{2} } + {12}^{2} [/tex]
[tex] {oa}^{2} = 81 + 144 [/tex]
OA = √225
OA = 15
