What’s the surface area of a cone with the height of 50 and a radius of 40

the surface area of a cone: πr²+πLr
L = the slant height
r = radius of the base
r = 40 in : 2 = 20 in
L = 50 in
The surface area:
=π.20² + π.50.20
=1256+3140
=4396 in²