Acircular area with a radius of 6.00 cm lies in the xy-plane. part a what is the magnitude of the magnetic flux through this circle due to a uniform magnetic field with a magnitude of 0.290 t in the + z -direction?

The magnetic flux through an area A is given by

where
B is the magnitude of the magnetic field
A is the area
is the angle between the direction of B and the perpendicular to the surface A.

In our problem, the area lies in the x-y plane, while B is in the z direction, this means that B and the perpendicular to A are parallel, so  and , so we can rewrite the formula as


We can calculate the area starting from the radius:

And then using the intensity of the magnetic field given by the problem, , we find the magnetic flux:

Ithink the answer would be a