1) In this problem, we're dealing with ratios and then we can write out the following:
[tex]16:9\Rightarrow\frac{16}{9}[/tex]2) Since the screen height is 22.3 and the aspect ratio we can write out the following proportion:
[tex]\begin{gathered} \frac{16}{9}=\frac{x}{22.3} \\ 9x=16*22.3 \\ 9x=356.8 \\ \frac{9x}{9}=\frac{356.8}{9} \\ x=39.64 \end{gathered}[/tex]3) Note that we need to consider a right triangle, in which the hypotenuse is the diagonal so we can write ou the following:
[tex]\begin{gathered} a^2=b^2+c^2 \\ a^2=\left(39.64\right)^2+\left(22.3\right)^2^ \\ a^=\sqrt{\left(39.64\right)^2+\left(22.3\right)^2} \\ a=45.48 \end{gathered}[/tex]Note that we used the Pythagorean relation.