Cross Product of Two Vectors

If $\left|\overrightarrow{a}\right|=13, \left|\overrightarrow{b}\right|=5$ and $\overrightarrow{a}\cdot \overrightarrow{b}=30$$,$ then $\left|\overrightarrow{a}\times \overrightarrow{b}\right|$ is equal to

Let $\overrightarrow{a}=\widehat{i}+\widehat{j}+\widehat{k},\overrightarrow{b}=\widehat{i}+3\widehat{j}+5\widehat{k}$ and $\overrightarrow{c}=7\widehat{i}+9\widehat{j}+11\widehat{k}$$.$ Then, the area of the parallelogram with diagonals $\overrightarrow{a}+\overrightarrow{b}$ and $\overrightarrow{b}+\overrightarrow{c}$ is