Given that this is a parallelogram, we know that 70°+(m-60)° has to equal 180°. So, we can set it up like this: 180-70=(m-60) and solve from there. The next step: 110= (m-60). Then, isolate the variable (add 60 on both sides):110+60=m. So, m=170.
To find the cost before tax, we must find out how much the tax is. So we multiply 252 x .05 to get 12.6. So we know the tax was 12.6 dollars. Now all we have to do is subtract that from the total to get our answer. 252 - 12.6 = 239.4.
