Answer:
a = 60km
Step-by-step explanation:
Pythagorean theorem: a² + b² = c²
a² + 32² = 68²
a² + 1024 = 4624
*subtract 1024 from both sides to isolate a² *
a² + 1024 - 1024 = 4624 - 1024
a² = 3600
*square root both sides to isolate a*
√(a²) = √3600
a = 60km