Complete missing outcrop problem
First step - draw a strike line where line A intersects the 400 m line.
Second step - you know that the sandstone layer is of equal thickness and dip, so you can draw a parallel line at the place with line B intersects the 400 m line. This will give you the thickness, as expressed on a horizontal surface. You know what the dip angle is, so getting the real thickness is simple trigonometry.
This should get you started.