Question

A chocolate cookie is a circular disk of diameter 8.50 ± 0.02 cm and thickness 0.050 ± 0.005 cm. The average volume in cm³ is

• A. 2.83 ± 0.3
• B. 2.38 ± 0.27
• C. 11.35 ± 1.2
• D. 9.31 ± 1.12

Answer 1

Answer: (A)

2.83 ± 0.3

Answer 2

V = πr²l $\frac{dV}{V} = \frac{2dr}{r} + \frac{dl}{l}$

V = $\frac{22}{7} \times \frac{8.5}{2} \times \frac{8.5}{2} \times 0.5$ dV = 2.83

$\left( \frac{2 \times .02}{8.5} + \frac{.005}{.050} \right) = 2.83\left( \frac{1}{21} + \frac{1}{10} \right)$ = 0.296 cm³

Thus V = 2.83 ± 0.3 cm³