Question

With explanation please, step by step if is necessary, I need heeelp!

Answer 1

`area \: of \: the \: circle \: = \: \pi {r}^(2) \\ so \\ \: 10 = \pi {r}^(2) \\ {r}^(2) = (10)/(\pi) \\ r = \sqrt{ (10)/(\pi) } \\ r = ( √(10) )/( √(\pi) ) \\ r = ( √(10) * √(\pi) )/( √(\pi) * √(\pi) ) \\ r = ( √(10\pi) )/(\pi) \\ since \: d \: = 2r \\ so \\ d = 2( ( √(10\pi) )/(\pi) ) \\ \\ d = (2 √(10\pi) )/(\pi) \\ since \: circumferenc \: = 2r\pi \\ so \: circumference = 2( ( √(10\pi) )/(\pi) )\pi \\ = 2( √(10\pi) ) \\ = 2 √(10\pi)`