$=($Cost at highest activity level $-$ Cost at lowest activity level$)/($Highest activity level $-$ Lowest activity level$)=($$$74,500-$ $$36,000)/(40,000$ units $-18,000$ units$)=$ $$38,500/22,000$ units $=$ $$1\mathrm{.}75$ per unit. Step $2$: Calculate the total variable cost at either activity level $=$ Variable cost per unit $*$ Activity level $=$ $$1\mathrm{.}75*40,000$ units $=$ $$70,000.$ Step $3$: Calculate the fixed cost $=$ Total cost at highest activity level $-$ Total variable cost at highest activity level $=$ $$74,500-$ $$70,000=$ $$4,500.$ So$,$ the unit variable cost is $$1\mathrm{.}75$ and the fixed cost is $$4,500.$ As for the contribution margin, it is calculated as Sales $-$ Variable Costs. determine the missing amounts for the contribution margin.