The rule of the volume of the solid shaped a rectangular solid is

L is the length
W is the width
H is the height
Since the dimensions of the room are
10 m long
5.6 m wide
155 m high
Then
L = 10
W = 5.6
H = 155
Substitute them in the rule above

The volume of the room is 8680 cubic meters
The rule of the mass is

m is the mass
d is the density
V is the volume
Since the density is 1.506 kg/m^3
Then d = 1.506
Since the volume is 8680 m^3
Then
![\begin{gathered} m=1.506*8680 \\ m=13072.08\operatorname{kg} \end{gathered}]()
The mass of the smoke inside the room is 13072.08 kg