Question

Determ lungimea unui cerc avand raza egala cu:
a) 8cm
b) 2 radical din 3
c) 3,5cm
d) 3 radical din 5 supra 2

Answer 1

$\it L_c=2\pi R\\ \\ a)\ \ L_c=2\pi\cdot8=16\pi\ cm\\ \\ b)\ \ L_c=2\pi\cdot2\sqrt3=4\pi\sqrt3\ cm\\ \\ c)\ \ L_c=2\pi\cdot3,5=7\pi\ cm\\ \\ d)\ \ L_c=\not2\pi\cdot\dfrac{3\sqrt5}{\not2}=3\pi\sqrt5\ cm$