Can anyone check my answer for a word problem?

Question

anonymous · Answer

0.448 for the problem:

anonymous · Answer

.A 4 kg block slides down a rough inclined plane inclined at 30° with the horizontal. Determine the coefficient of kinetic friction between the block and the surface if the block has an acceleration of 1.2 m/s2.

jfraser · Answer

I get 0.436, but 0.448 is an acceptable answer, I'd say

anonymous · Answer

I get 0.437 $$\mu = \frac{14.8}{33.9}$$

anonymous · Answer

1. 4 x 9.8 x sin30 = 19.6 N

2.The net force along the plane is 4x1.2 = 4.8 N

3. The force of friction is 19.6-4.8 = 15.2 N = muf x 4  x 9.8 x cos30 

4.The coefficient of friction, muf = 15.2/(4 x 9.8 x cos30)

anonymous · Answer

this is my work, where did i go wrong @ghuczek

anonymous · Answer

Check your calculations for the force of friction: 19.6 - 4.8 = 14.8