The teaching building is in the south of the school gate 150 meters, and the experimental building is 200 meters southwest of the school gate.

Because the distance of 1 cm on the map indicates the actual distance of 50 meters,

Then 150÷50=3 cm,

100÷50=2 cm,

200÷50=4 cm,

50÷50= 1 cm,

Because the teaching building is just south of the school gate.

The electronic piano room is 30 degrees south of the school gate.

The computer room is 45 degrees east-south of the school gate.

The library is 60 degrees south of the school gate.

You are standing in the north of the school gate.

So their positions are shown in the following figure: