The triangles in the diagram below are similar. Find the distance across Clarence Lake. ( Figure may not be drawn to scale)

Answer: 40 km
Step-by-step explanation:
As corresponding sides of similar triangles are proportional, if we let the distance across Clarence lake be x,
[tex]\frac{x}{8}=\frac{15}{3}\\\\\frac{x}{8}=5\\\\x=\boxed{40 \text{ km}}[/tex]