Answer: 11.4 m
Explanation:
The scenario depicted is that of a right angled triangle with the 7 meters being the base and the 9 meters being the height.
The length of the ladder will therefore be the Hypothenuse.
Using the Pythagorean Rule:
a² + b² = c²
with c being the hypothenuse
7² + 9² = c²
49 + 81 = c²
c²= 130
c = √130
c = 11.4 m