A circus tent is cylindrical to a height of 4 m and conical above it.

We have,

Height of the cylindrical part, $H=4 \mathrm{~m}$,

Radius of the base, $r=\frac{105}{2} \mathrm{~m}$ and

Slant height of the conical part, $l=40 \mathrm{~m}$

Now,

The total area of canvas required = CSA of conical part + CSA of cylindrical part

$=\pi r l+2 \pi r H$

$=\pi r(l+2 H)$

$=\frac{22}{7} \times \frac{105}{2} \times(40+2 \times 4)$

$=11 \times 15 \times 48$

$=7920 \mathrm{~m}^{2}$

So, the area of the canvas required to make the tent is 7920 m2.