Step-by-step explanation:
[tex]circumference \: of \: circle = 2\pi \: r \\ \\ \therefore \: 451 = 2 \times 3.14 \times r \\ \\ \therefore \: 451 = 6.28 \times r \\ \\ \therefore \: r = \frac{451}{6.28} \\ \\ \therefore \: r = 71.8152866 \\ \\ \therefore \: r \approx 71.8 \: cm \\ \\ [/tex]
