Poulan Pro 271490 Owner's Manual page 47

SUGGESTED GUIDE FOR SIGHTING SLOPES FOR SAFE OPERATION
1. Fold this page along dotted line indicated above.
2. Hold page before you so that Its left edge is vertically parallel to a tree
trunk or other upright structure,
3. Sight across the fold in the direction of hill slope you want to measure.
4. Compare the angle of the fold with the slope of the hill.