Chapter: Pythagoras Theorem· Mathematics Part 2 (Geometry)
Answer: 5 m
The wall, the ground and the ladder form a right-angled triangle with the ladder as hypotenuse.
\(d^2 + 12^2 = 13^2\) \(\therefore d^2 = 169 - 144 = 25\) \(\therefore d = 5\) m.