He radius of a circle is 2 kilometers. what is the area of a sector bounded by a 45° arc?

We know that
area of a circle=pi*r²
for r=2 km
area of a circle=pi*2²> 12.56 km²

if 360° (full circle) has an area of> 12.56 km²
 45°> x
x=45*12.56/360> x=1.57 km²

the answer is
1.57 km²