Question

Aflati raza bazei unui cilindru circular drept cu aria totala de 13pi $cm^{2}$ si generatoarea de $1 \frac{1}{4}$ $cm^{2}$

Answer 1

[tex]\it \mathcal{A}_t = 2\pi R(R+G) \\\;\\ 13\pi = 2\pi R(R+\dfrac{5}{4}) \Rightarrow 13 = 2 R\dfrac{4R+5}{4}\Rightarrow 13=\dfrac{R(4R+5)}{2} \Rightarrow \\\;\\ \\\;\\ 26=R(4R+5) \Rightarrow R = 2[/tex]