Determine which of the following equations model exponential decay
a ) k(x) = 85(2x)^48
b ) f(x) = .0382(4)^x
c ) g(x) = (.825)^8x -11
d ) h (x) = 985 (1) ^x

314.16 m

Step-by-step explanation:

The distance across the track is 100 metres. This means that the diameter is 100 m.

The track is circular, so, we need the circumference.

The circumference of a circle is given as:

C = πD

where D = diameter

Therefore, the circumference of the track is:

C = π * 100 = 314.16 m

She walked a distance of 314.16 m