Consider the following figure.

Answer:
BD = 16
Step-by-step explanation:
By applying mean proportional theorem in the given right triangles,
[tex]\frac{AD}{BD}=\frac{BD}{CD}[/tex]
AD × CD = BD²
8 × 32 = BD²
BD = √256
BD = 16
Therefore, measure of side BD = 16 units.