Question 1169618
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It’s initial circumference was 80 cm and it grows at a rate of 2 cm every year. This situation can be represented by the equation C = 80 + 2t
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That is everything you need.
C, the circumference at any time t in years;
Slope is seen for how many cm's per year;
and the initial size was the constant term.


You only need to know 2pi*r=C for question part (d).