👤

AJUTATI VA ROG FRUMOS, VA DAU 5 STELE​

AJUTATI VA ROG FRUMOS VA DAU 5 STELE class=

Răspuns :

  • Lcerc = 2pi×r

6.

a) D=10cm

D= 2r => r=10/2= 5 cm

L cerc= 2×5×pi= 10pi

b) D= 6 intregi 2/5 cm= 32/5

D= 2r => r= 32/5 ÷ 2= 32/5 × 1/2= 16/5 cm

L cerc= 2× 16/5 ×pi= 32/5pi= 6,4 pi

c) D=1 /pi cm

r= 1/pi÷2= 1/pi × 1/2= 1/ 2pi

L cerc= 2× 1/2 × pi= pi