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8. Calculați aria discului cu diametrul de: a) 8 cm; b) 1 / 2 cm; c) πT 10 cm.​

Răspuns :

[tex]\it a) \ \ R = 8:2=4\ cm;\ \ \mathcal{A}=\pi R^2=\pi\cdot4^2=16\pi\ cm^2\\ \\ \\ b)\ \ R=\dfrac{1}{2}:2=\dfrac{1}{4}=0,25\ cm;\ \ \ \mathcal{A}=\pi\cdot0,25^2=0,0625\pi\ cm^2[/tex]

Răspuns:

arie disc=pi*r^2

r=d/2

r=raza disc d=diametru disc

r=8/2=4 cm

a=pi*16 cm2

r=1/2:2=1/4

a=pi*1/16 cm 2

r=10*pi/2=5pi

a=pi*25*pi^2 cm2=25*pi^3 cm2