we are given
172(60÷m)=80
[tex] 172(\frac{60}{m})=80 [/tex]
we will isolate m on any one side
step-1: Multiply both sides by m
[tex] 172(\frac{60}{m})*m=80*m [/tex]
[tex] 172*60=80*m [/tex]
step-2: Divide both sides by 80
[tex] (\frac{172*60}{80})=m [/tex]
[tex] m=129 [/tex]..............Answer