Whats the area of a quarter-circle with diameter of 4 meters

The answer is 3.14 m

The area (A) of the circle with radius r is: A = π · r²
The area of the quarter of the circle is: A1 = 1/4A = 1/4 · π · r²

We have:
A1 = ?
r = ?
π = 3.14
d = 4 m

A diameter d is the twice of the radius r: d = 2r.
Therefore, the radius is the half of the diameter: r = d/2
So, the area of the quarter circle would be:
A1 = 1/4 · π · r² = 1/4 · π · (d/2)² =1/4 · π · d²/2² = 1/4 · π · d²/4 = 1/16 · π · d²

A1 = 1/16 · π · d² = 1/16 · 3.14 · 4² = 1/16 · 3.14 · 16 = 3.14 m