Last year Triangular Resources earned $ $5\mathrm{.}2$ million in net operating income and had an operating profit margin of $20\mathrm{.}3$ percent. If the$$ firm's total asset turnover ratio was $1\mathrm{.}42,$ what was the$$ firm's investment in total$$ assets?

Please show work, the exercises in the book are not helping me$.$ Thanks!