"The oranges are red."
Translation:संतरे लाल हैं।
The color orange in Hindi is नारंगी (which incidentally shares the same root as the English word). You can also use नारंगी to refer to the fruit though संतरा is somewhat more common.
Fun fact: The top third of the Indian flag is not actually नारंगी. It is केसरी (saffron) colored.