You don't need an angle to solve this one!! But if you wanted to, the angle would be 90 degrees. Here's the way I would solve it....

Formula : Φ=BA

Area of the Floor: 104m2

Area of the Wall: 27m2

Magnetic Field (horizontal): 3.0 x 10-5T

Magnetic Field (vertical): 3.4 x 10-5T

a) The magnetic flux through the wall if the wall faces north

Φ = BA

= (3.0 e-5 T) * (27m2)

= _____ Wb

b) The magnetic flux through the wall if the wall faces east

Φ = 0 Wb

c) The magnetic flux that passes through the floor

Φ = BA

= (3.4 x e-5T) * (104m2)

= ______ Wb