As D lies on BC, the distance from D to BC is 0.
If we let the distance from D to AB be x, then in the right triangle,
[tex]\sin 30^{\circ}=\frac{x}{8}\\\\\frac{1}{2}=\frac{x}{8}\\ \\ x=4[/tex]
This means the distance from D to side AB is 4.
We can note that [tex]\sin 30^{\circ}=\frac{x}{8}=\frac{y}{8}[/tex], meaning y=4 as well, and thus the distance from D to side AC is 4
