Finding the Missing Angle
There are three different angles:
<ABC (the larger angle)
<ABD (one angle that makes up the larger angle)
<DBC (the other angle that makes up the larger angle)
By clicking and dragging a point on one of the rays, you can change the measurement of each of the angles. <DBC is missing. You can calculate the missing angle by subtracting the smaller angle (<ABD) from the larger angle (<ABC).