surface area of a cone

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What is the surface area of a cone with height $h$ not including the base?

I know a cone can be parameterized by $F(u, v) = (u cos v, u sin v, u)$ for $u ≥ 0$.

I believe the parameterization is not regular, so why is the calculation is still valid?

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Let the circumference of base be $2\pi.R$
Now, $2\pi.R=l\theta$, When we open the cone giving $\theta=\frac{2\pi.R}{l}$
Now $SA_{cone}=(\frac{\theta}{360^o})*\pi.l^2=\pi.Rl$