Answer:
5km
Step-by-step explanation:
Please check the attached image for a diagram explaining this question
The distance from A to C can be determined using Pythagoras theorem
The Pythagoras theorem : a² + b² = c²
where a = length
b = base
c = hypotenuse
3² + 4²
= 16 + 9
= 25
determine the square root of 25
√25 = 5km
60.7420...
The lamppost is 20 feet long.