Golden Triangle is the most popular tourist circuit of North India. Golden triangle term applies to Delhi/Agra/Jaipur.
Tour is blend of English, Mughal, Hindu rule in India. Where in Delhi you have oppotrunity to know about English and Mughal rule in India, on other hand in Agra, you can see Mughal's time buildings & Jaipur know as Pink City is fomous for Hidus's palaces like Amber Fort & City Palace.
There are serveral other tourist places you can club with golden Triangle Tour. Some are

1 . Delhi-Jaipur-Agra-Varanasi-Delhi
2 . Delhi-Mandawa-Jaipur-Agra-Delhi
3 . Delhi-Agra-Jaipur-Udaipur-Delhi
4 . Delhi-Jaipur-Agra-Delhi-Rishikesh-Delhi

Know more about Agra, Jaipur

Agra - Agra was the capital of the Mughal empire in the 16th and 17th century and its significance as a political centre ended
with the transfer of the capital in Delhi in 1634 AD by Shah Jahan. But wealth Taj Mahal has secured its place on the international Map.Agra is also known as its superb inlay work on marble and soapstone.
Place to visit Agra - Taj Mahal, Agra Fort, Itmad-Ud-Daulah's Tomb.

Jaipur - Capital state of Rajasthan has earned Universal renown as "Pink City".Jaipur meaning 'city of victory' was founded in 1727 by the astronmer king Sawai Jai Singh.
Attractive monuments,comfortable hotels, gardens and excursion nearby places and shopping makes the Pink City as memorable one.

Places to visit Jaipur - City Palace, Jantar Mantar, Wind Palace, Amber Fort, Water Palace,Birla Temple
Distances from Jaipur - Delhi - 259kms, Agra 230kms, Bhartpur 176kms, Ajmer 132kms, Udaipur 407kms, Jodhpur 343kms