Please refer to video for the figure.
Area of material used for making fez, `A` = Curved Surface Area of frustum + Area of circular part at the top of fez
So, `A = pi**(r_1+r_2)**l +pir_2^2`
Here, `l = 15, r_1 = 10 and r_2 = 4`
Putting these values,
`A = pi(10+4)**15+pi**16=226**22/7 ~= 710.6cm^2`