Question

The diameter of a rubber ball is one-third of diameter of a plastic ball. Find the ratio of their surface areas.

please tell in 5 mins its very urgent

Answer 1

Answer:

$let\: \: the \: \: diameter \: \: of \: \: plastic \: \:ball \: = x \\ so \: \: radius \: \: of \: \: plastic \: \: ball \: \: = \: \: \frac{x}{2} \\ and \: \: radius \: \: of \: \: rubber \: \: ball \: \: = \: \: \frac{x}{6} \\ now \: \: the \: \: surface \: \: area \: \: of \: \: sphere \: \: = \: \: 4\pi {r}^{2} \\therefore \: \: surface \: \: area \: \: of \: \: plastic \: \: ball \: \: = \: \: 4 \: \times \frac{22}{7} \: \times \frac{ {x}^{2} }{ {2}^{2} } \\ = 4 \: \times \frac{22}{7} \: \times \frac{ {x}^{2} }{4} \: = \frac{22 {x}^{2} }{7} \\ and \: \: surface \: \: area \: \: of \: \: rubber \: \: ball \: \: = \: \: 4 \: \times \: \frac{22}{7} \: \times \frac{ {x}^{2} }{ {6}^{2} } \: \\ = 4 \: \times \frac{22}{7} \times \: \frac{ {x}^{2} }{36} \: = \: \frac{22 {x}^{2} }{63} \\ so \: \: ratio \: \: of \: \: their \: \: surface \: \: area \: \: = \: \: \frac{22 {x}^{2} }{7} \frac{.}{.} \frac{22 {x}^{2} }{63} \\ = \frac{22 {x}^{2} }{7} \: \: \times \: \: \frac{63}{22 {x}^{2} } \: \: = \: \: 9$

hope this answer will help you.

Answer 2

$\huge\underline\bold\blue{AnswEr✓}$

☞heyya...

☞ see in the attachment pasted above