Calculate the Given Quantities If $\mathbf { a } = \mathbf { i } - 9 \mathbf { j } \text { and } \mathbf { b } = - 9 \mathbf { j } + 4 \mathbf { k }$

Short Answer

Calculate the given quantities if $\mathbf { a } = \mathbf { i } - 9 \mathbf { j } \text { and } \mathbf { b } = - 9 \mathbf { j } + 4 \mathbf { k }$ I. $\quad \mathbf { a } \cdot \mathbf { b }$
II $\mathbf { a } \times \mathbf { b }$
III. The angle between $\mathbf { a }$ and $\mathbf { b }$ (correct to the nearest degree)