m= mass = 24.8 kg
g= 9.8 m/s^2
u= coefficient of friction = 0.51
N1 = normal force on wall
N2= normal force due to horizontal floor
N2= mg = 24.8 * 9.8 = 243.04 N
Friction force: (FR)
Fr = u N = 0.51 * 243.04= 123.9504 N
Fr * tan Ф = mg
123.9504 * tan Ф = 24.8 * 9.8
Ф = 62.98°