A highway is being constructed to accommodate traffic for speeds of 12.0 m/s. If the angle of the bank is 8.07° and there is no friction force, what is the highway's curve radius?

This is your homework. Show us your work and what you think the answer is... and we can help. But we will not do your assignment so you don't have to. You learn nothing that way,

Hint: you need to balance the force due to centripetal acceleration with the force due to gravity of sliding down the incline. Show us your attempt at this and we'll check it for you.