Finding bearings

In all the questions place the blue dot where you are standing and place the red dot onto the target red dot.

1. What is the bearing of the school from the park (meaning you are standing at the park)?

2. What is the bearing of the school from the house?

3. What is the bearing of the house from the school (the back bearing of the question before)?

4. What is the bearing of the house from the park?

5. What is the bearing of the park from the house (the back bearing) ?

6. Have you noticed a quick way to calculate the back bearing?