Answer:
Architects continue to use classical precedents in the 18th and 19th centuries like the ones used as an example because they are incredibly representative works that revolutionized the cultural environment and remained as a stepping stone of architecture and art for their use of classical works of previous eras.
Explanation:
All right, here we are talking about something very common. The cultural value of art/ architecture works inspired or influenced by very classical references like greek, roman, baroque, and many other styles and eras. Therefore, they are used as an example. Because they represent a modern classical-inspired work that recreates the classic characteristics in its best level of performance. Also, because they leave a cultural footprint in the postmodernity of human achievement, talent, and work.