A Granular Substance Such as Sand Naturally Settles into a Cone-Shaped

Multiple Choice

A granular substance such as sand naturally settles into a cone-shaped pile when poured from a small aperture.Its height depends on the humidity and adhesion between granules.The angle of elevation of a pile,θ,is called the angle of repose.If the height of a pile of sand is 14 feet and its diameter is approximately 47 feet,determine the angle of repose.Round your answer to the nearest degree.

A) $27 ^ { \circ }$
B) $29 ^ { \circ }$
C) $28 ^ { \circ }$
D) $30 ^ { \circ }$
E) $31 ^ { \circ }$