Page 138 - Nutrient Management Planning Guide

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Estimating Manure Inventory

Key Mathematical Relationship of a Right Angle Triangle

Figure 4.1.12 Labeled Right Angle Triangle (rotate 90 degrees)

The graphic (Figure 4.1.12) represents a right angle triangle with the sides labeled in terms of angle ‘A’. Any of the sides or angles of a right-angled triangle can be solved if the measurement for at least one angle (in addition to the 90 degree angle) and one side are known. This mathematical principle will be used to calculate the height (depth) of manure in a tapered prism storage facility.

Rest the board on the slope of the storage wall with at least 30 cm (1 ft) projecting above the top of the storage wall. Place the board on its narrow edge such that the broad face is visible in side profile (Figure 4.1.13A).

Place the carpenter’s level against the face of the board above the top of the storage wall (Figure 4.1.13B). Draw a level horizontal line along the face, using the carpenter’s level as a guide. Use the protractor to measure the angle formed between the line and the bottom edge of the board that rested on the wall of the manure storage (Figure 4.1.13C). This will be referred to as the measured slope angle of the facility wall.

Figure 4.1.13 Estimating Slope on the Wall of an Earthen Manure Storage Facility