Radios setll for $50 each

Fixed costs total $121,690

Variable Costs are $40 per unit

I figured out the contribution margin/ unit is $10 per unit

Break Even point is $608,450

Margin of Sfaety ratio assuming actual sales of $860,000 is 29.25%

I know the formula to calulate sales dollars required to earn net income of $248,310 (fixed costs + target net income divided by contribution margin ratio.

How do I find that contribution margin ratio?