page 219 - you need to determine each building's vanishing points separately as the two buildings may be at different angles.

house on page 222 - the small house on page 221 has a small bit chopped off the top, other wise they are the same building.

When you extend the lines of the building out to the vanishing point, they will meet on the horizon. A quick way to check where the horizon is going to be is to look on the building and find where the lines run horizontal. The horizon will be there. All lines above that will run downwards and all lines under the horizon will run upward to meet the horizon.

Let me know if that help?