Answer:
r = 3.95 mm (nearest hundredth)
Step-by-step explanation:
[tex]\textsf{volume of a cylinder} = \pi r^2h[/tex]
(where r = radius and h = height)
Given, volume = 686 mm² and height = 14 mm:
[tex]686=\pi r^2\times14[/tex]
[tex]\implies\pi r^2=686 \div14=49[/tex]
[tex]\implies r^2=49 \div \pi[/tex]
[tex]\implies r=\sqrt{49 \div \pi }=3.949327085...[/tex]
[tex]\implies r=3.95 \ \textsf{mm}[/tex]
