Approximation Math Example 2

Solution

1. 1
   Using $\pi \approx \dfrac{22}{7}$: Circumference $= 2\pi r = 2 \times \dfrac{22}{7} \times 14 = 2 \times 44 = 88$ cm.
2. 2
   Area $= \pi r^2 = \dfrac{22}{7} \times 196 = 22 \times 28 = 616$ cm$^2$.
3. 3
   Using $\pi \approx 3.14159$: Circumference $\approx 87.96$ cm; Area $\approx 615.75$ cm$^2$.
4. 4
   Error: $|88 - 87.96| = 0.04$ cm ($\approx 0.05\%$); area error $\approx 0.25$ cm$^2$ ($\approx 0.04\%$).