Answer:
13 km
Step-by-step explanation:
The area formula for a triangle is ...
A = (1/2)bh
We are told that b=2h, so this becomes ...
A = (1/2)(2h)(h) = h²
Substituting the given area, we can find h:
169 km² = h²
(√169) km = h = 13 km
The height is 13 km.