A circular garden with a diameter of 20 meters is surrounded by a walkway of width 1 meter. What is the area of the walkway?

Question: A circular garden with a diameter of 20 meters is surrounded by a walkway of width 1 meter. What is the area of the walkway?

Solution:
Given that,
Radius of the garden = 20/2 = 10 m
Width of walkway = 1 m
So, radius of the outer circle (garden + walkway) = 10 + 1 = 11 m

We know,
Area of circle = πr²

Now,
Area of outer circle = π × (11²) = π × 121 = 121π m²
And,
Area of inner circle (garden only) = π × (10²)= π × 100 = 100π m²

Now,
Area of walkway = Area of outer circle - Area of inner circle = (121π - 100π) m² = 21π m²

So the area of the walkway = 21π m²