L cerc = 2πR = 2π x 18 = 36π cm
360° ..... 36π
30° ........x ⇒ direct proportionale
⇒ 360/30 = 36π/x ⇒ 12 = 36π/x ⇒ x=36π/12 = 3π cm
Sper sa te ajute!
Răspuns:
[tex]\red{\boxed{\bf L_{cerc} =2\cdot\pi\cdot r }}[/tex]
[tex]\bf r = 18~cm[/tex]
[tex]\bf L_{cerc} =2\cdot\pi\cdot 18\implies L_{cerc} =36\cdot\pi ~cm[/tex]
[tex]\bf Notam ~cu ~\blue{x}~masura ~arcului~ de ~cerc ~cu~ masura~ de~ 30^{\circ}[/tex]
[tex]\bf 360^{\circ} ................36\cdot\pi[/tex]
[tex]\bf\underline{ 30^{\circ} ................ x~~}[/tex]
[tex]\bf\dfrac{^{30^{\circ})~} 360^{\circ}}{30^{\circ}} =\dfrac{36\cdot\pi }{x} \Rightarrow 12=\dfrac{36\cdot\pi }{x}\Rightarrow 12x=36\cdot\pi[/tex]
[tex]\bf \Rightarrow x=36\cdot\pi:12\Rightarrow \red{\boxed{\bf x=3\cdot\pi~~cm}}[/tex]
[tex]==pav38==[/tex]
