I mean Mensuration and Boats and Streams are important or not??
you can check the sites below to see weightage of all the topics and their subtopics.
Youth4work, testbook etc
MENSURATION
Weightage: 2-4 Qs
Easy to Moderate in Difficulty, Moderately Time Consuming, High Accuracy Possible.
Train, Boat & Stream
Weightage: 2-3 Qs