Answer:
3.41 feet
Step-by-step explanation:
Area = Length × Breath
Area of the rectangular lawn = 100 × 50
= 5000 feet²
The sidewalk must occupy an area no more than 10% of the total lawn area.
So, the area of the sidewalk would be not more than = 10% × 5000
= 0.10 × 5000
= 500 feet²
Let the width of the sidewalk = x feet
area of the side walk = (L×W of the long way) + ((L-x)×W of the short way)
(100 × x) + ((50 - x) × x) < 500
100x + (50-x)(x) < 500
-x² + 150x < 500
-x² + 150x = 500
-x² + 150x - 500 = 0
By using quadratic formula
or
x = 3.41089 ≈ 3.41 feet or x = 146.58
Therefore, width of the sidewalk would be 3.41 feet.