To create your own interactive content like this, check out our new web site doenet.org!
Image: Area of parallelogram
The area of a parallelogram with spanned by the vectors $\vc{a}$ and $\vc{b}$ is $$\|\vc{a}\|~\|\vc{b}\|\sin\theta,$$ where $\theta$ is the angle between $\vc{a}$ and $\vc{b}$.