jmc

The area of trapezoid $CBFE$ is $\frac{1+3}{2}\cdot 4=8$. Next, we find the height of each triangle to calculate their area. The two non-colored isosceles triangles are similar, and are in a $3:1$ ratio by AA similarity (alternate interior and vertical angles) so the height of the larger is $3,$ while the height of the smaller one is $1.$ Thus, their areas are $\frac{1}{2}$ and $\frac{9}{2}$. Subtracting these areas from the trapezoid, we get $8-\frac{1}{2}-\frac{9}{2}=\boxed{3}$. Therefore, the answer to this problem is $\boxed{3}$