87. Figure $1.11 \mathrm{c}$ shows a parallelogram based on the two vectors $\overrightarrow{\boldsymbol{A}}$ and $\overrightarrow{\boldsymbol{B}}$ (a) Show that the magnitude of the cross product of these two vectors is equal to the area of the parallelogram. (Hint: Arca $=$ base $\times$ height. (b) What is the angle between the cross product and the plane of the parallelogram?

 87. Figure $1.11 \mathrm{c}$ shows a parallelogram based on the two vectors $\overrightarrow{\boldsymbol{A}}$ and $\overrightarrow{\boldsymbol{B}}$ (a) Show that the magnitude of the cross product of these two vectors is equal to the area of the parallelogram. (Hint: Arca $=$ base $\times$ height. (b) What is the angle between the cross product and the plane of the parallelogram?