To solve a proportion first the two numbers that are diagonal.

we have
[tex]\begin{gathered} \frac{2100}{30}=\frac{x}{45} \\ 30\times x=45\times2100 \\ 30x=94500 \\ \frac{30x}{30}=\frac{94500}{30} \\ x=3150 \end{gathered}[/tex]answer: 3,150 times every 45 minutes