Draw rough diagrams of two angles such that they have four points in common.
 

 Identify how many triangles are there in the figure.

Write the names of seven angles.

 Write the names of six line segments.

If $\angle k$ is the common angle of two triangles $∆\mathrm{ABC} \mathrm{and} ∆\mathrm{ABD}$, then write the vertex of $\angle k$.