What is the perimeter of a square with a 13ft side

My favorite songstress gives away 25% of this side of her signature fragrance collection to her charity last month her sales were 1200 how much of her sales did she donate

What are the constants in this expression? -10.6+9/10+2/5m-2.4n+3m

Equation for the calculation double 2 and then add 5