Write the Word or Phrase That Best Completes Each Statement $$\mathbf { m } = \mathbf { i } - 4 \mathbf { j } + 5 \mathbf { k } \text { and } \mathbf { b } = - 2 \mathbf { i } + 3 \mathbf { j } + \mathbf { k }$$

Write the word or phrase that best completes each statement or answers the question.
Solve the problem.
-A sail on a sailboat is supported by a mast and a boom. The length and direction of the mast and boom can be
described by the vectors , respectively, where the components are in meters. $$\mathbf { m } = \mathbf { i } - 4 \mathbf { j } + 5 \mathbf { k } \text { and } \mathbf { b } = - 2 \mathbf { i } + 3 \mathbf { j } + \mathbf { k }$$ Find the angle (to the nearest tenth of a degree) between the mast and boom.