Question

Calcule o valor da circunferência quando:
A) r= 25 cm
B) d= 7,5 cm
C) r= 0,86 km
D) d= 100m


URGENTE!!

Answer 1

$c = 2\pi r$


a)

$c = 2\pi \times 25$

$c = 50\pi = 157cm$


b)

$r = \frac{d}{2}$

$c = 2\pi \times ( \frac{7.5}{2} )$

$c = 2\pi \times \frac{15}{4}$

$c = \frac{15\pi}{2} = 23.56cm$


c)

$0.86km \times 1000 = 860m$

$c = 2\pi \times 860$

$c = 1720\pi$

$c = \frac{1720\pi}{1000}$

$c = \frac{43\pi}{25} = 5.4km$


d)

$r = \frac{d}{2}$

$c = 2\pi \times ( \frac{100}{2})$

$c = 2\pi \times 50$

$c = 100\pi = 314.16m$