👤

1.Aflati axa si volumul sferei cu baza de 10 dm . 2. Aflati aria laterala , aria totala si volumul unei con circular drept cu generatoarea de 10 m si inaltimea 8 m . 3. Aflati aria laterala , aria totala si volumul unei prisme triunghiulare cu muchia bazei de 7 cm si inaltimea de 10 cm .

Răspuns :

   
[tex]\displaystyle \\ 1) ~~\text{Aflati aria si volumul sferei cu raza de 10 dm.} \\ \\ ~~~~~~~A = 4\pi R^2= 4\pi \times 10^2=4\pi \times 100= \boxed{400\pi~dm^2}\\\\ ~~~~~~~V = \frac{4\pi R^3}{3} = \frac{4\pi 10^3}{3} =\frac{4\pi 1000}{3} = \boxed{\frac{4000\pi}{3}~dm^3 } [/tex]


[tex]\displaystyle \\ 2)~~\text{Aflati aria laterala , aria totala si volumul unei con circular rept } \\ \text{cu generatoarea de 10 m si inaltimea 8 m .} \\ \\ \text{Aplicam Pitagora in pentru a afla raza.} \\ \\ R = \sqrt{G^2 - h^2}=\sqrt{10^2-8^2}=\sqrt{100-64}=\sqrt{36} = \boxed{6~m} \\ \\ A_l = \pi RG = \pi \times 6 \times 10 = 60\pi~m^2 \\ \\ A_t = \pi RG + \pi R^2 = \pi R(G+R) = \\ \pi \times 6(10+6)= \pi \times 6 \times 16= \boxed{96\pi~m^2} [/tex]

[tex]\displaystyle \\ V = \frac{\pi R^2 h}{3}= \frac{\pi 6^2 \times 8}{3}= \frac{\pi \times 36 \times 8}{3}= \pi \times 12 \times 8 = \boxed{96 \pi~m^3}[/tex]


[tex]\displaystyle \\ 3)~~~\text{Aflati aria laterala , aria totala si volumul unei prisme } \\ \text{prisme triunghiulare cu muchia bazei de 7 cm si inaltimea de 10 cm.} \\ \\ A_l = P_b \times h = 3l \times h = 3\times 7 \times 10 = \boxed{210~cm^2} \\ \\ A_b = \frac{B \times I}{2} = \frac{l \times \frac{l \sqrt{3} }{2} }{2} = \frac{l^2 \sqrt{3} }{4} = \frac{7^2 \sqrt{3} }{4} = \boxed{\frac{49 \sqrt{3} }{4} ~cm^2} [/tex]


[tex]\displaystyle \\ A_t = A_l + 2 A_b = 210 + 2\times \frac{49 \sqrt{3} }{4} = \boxed{210 + \frac{49 \sqrt{3} }{2} ~cm^2} \\ \\ V = A_b \times h = \frac{49 \sqrt{3} }{4} \times 10 = \frac{49 \sqrt{3} }{2} \times 5 = \boxed{\frac{245 \sqrt{3} }{2} }[/tex]