Помогите решить !!!! Номер 200

правилом "крест-накрест" [latex]1)[/latex] [latex] \frac{a}{5} = \frac{6}{15} [/latex] [latex]5 * 6 = 15a[/latex] [latex]30 = 15a[/latex] [latex]a = 2[/latex] [latex]2)[/latex] [latex] \frac{1}{12} = \frac{4}{a} [/latex] [latex]a = 12 * 4 = 48[/latex] 3) [latex] \frac{56}{70} = \frac{8}{a} [/latex] [latex]56a = 70* 8[/latex] [latex]56a = 560[/latex] [latex]a = 10[/latex] [latex]4)[/latex] [latex] \frac{a}{60} = \frac{6}{5} [/latex] [latex]5a = 60*6[/latex] [latex]5 a = 360[/latex] [latex]a= 72[/latex]