a The given triangle is right-angle triangle.
So, we can use the Pythagoras formula,
[tex]H^2=P^2+B^2\ldots(1)[/tex]
Here,
[tex]\begin{gathered} H=10 \\ B=8 \end{gathered}[/tex]
Then from equation (1)
[tex]\begin{gathered} H^2=P^2+B^2 \\ (10)^2=P^2+(8)^2 \\ P^2=100-64 \\ P^2=36 \\ P=\sqrt[]{36} \\ P=6 \end{gathered}[/tex]
So, the required number of dominoes is 6.
Hence, the correct option is option A.
