How Do I Calculate the Focal Distance?

[SFBKR]

I cannot figure out focal distance and the like, is there anyway I can get a walkthrough?
the radius of curvature (R) to 0.7 m and the lens’s refractive index (n) to 1.8 . anyone?

 

[tiny-tim]

Welcome to PF!

Hi SFBKR! Welcome to PF!

I cannot figure out focal distance and the like, is there anyway I can get a walkthrough?
the radius of curvature (R) to 0.7 m and the lens’s refractive index (n) to 1.8 . anyone?

What equations do you think will help?

Show us how far you get.