Hello Student,

As per my knowledge, there is bit similarities on the architectural designing of Taj Mahal and red Fort. Taj Mahal was made by Mughal emperor Shah Jahan, which is a amalgamation of Persian and Mughal architecture main by the influence of Indian architecture as well. The whole structure is built with white marble and some precious and semi precious stones.

On the other hand red Fort is also build by Shah Jahan and the architecture type is the blend of Indo  Islamic and Mughal architecture. Few parts are made with red stone. But most of the part is made also with marble.

So that similarities are those.