Answer
$340$ m$^2$
Work Step by Step
The total area is the sum of the lateral area and the area of the bases.
In this case, we have one, square base , with a side length of 10m.
$B=10^2=100$ m$^2$
Lateral area $=240$m$^2$
Add both to get the total area:
$240+100=340$ m$^2$