Question

A)qual é o comprimento da circunferencia cujo diâmetro e 8,5 B)diâmetro =8,75C)o raio =2,85D)o diâmetro = 8

Answer 1

$C=2 \pi r$

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

a)

$\frac{d}{2}=r \\ \frac{ \frac{17}{2} }{2} =r \\ \frac{17}{2}* \frac{1}{2}=r \\ \frac{17}{4} =r$

$C=2 \pi r \\ C=2 \pi \frac{17}{4} \\ C= \frac{17}{2} \pi$

b)

$\frac{d}{2}=r \\ \frac{ \frac{35}{4}}{2}=r \\ \frac{35}{4}* \frac{1}{2}=r \\ \frac{35}{8}=r$

$C=2 \pi r \\ C=2 \pi \frac{35}{8} \\ C= \frac{35}{4} \pi$

c)

$r= \frac{57}{20} \\ C=2 \pi r \\ C=2 \pi \frac{57}{20} \\ C=57/10 \pi$

d)

$\frac{d}{2} =r \\ \frac{8}{2}=r \\ 4=r \\ C=2 \pi r \\ C=2 \pi 4 \\ C=8 \pi$