◈ Area of square room :
[tex]:\implies\sf\:A_s=(side)^2[/tex]
[tex]:\implies\sf\:A_s=(12)^2[/tex]
[tex]:\implies\bf\:A_s=144\:m^2[/tex]
◈ Area of triangular carpet :
[tex]:\implies\sf\:A_t=\dfrac{1}{2}\times base\times perpendicular[/tex]
[tex]:\implies\sf\:A_t=\dfrac{1}{2}\times 10\times 8[/tex]
[tex]\:\implies\sf\:A_t=\dfrac{1}{2}\times 80[/tex]
[tex]:\implies\bf\:A_t=40\:m^2[/tex]
◈ Uncovered area of room :
[tex]:\implies\sf\:\Delta A=A_s-A_t[/tex]
[tex]:\implies\sf\:\Delta A=144-40[/tex]
[tex]:\implies\:\boxed{\bf{\blue{\Delta A=104\:m^2}}}[/tex]