Yes maths is compulsory for NATA B. Arch. 

ABOUT NATA

NATA, National aptitude test for architecture, is an entrance exam which is conducted by National Institute of advanced studies in architecture (NIASA) the body of council of Architecture in India. This entrance exam is a national level examination. Students who are willing to study Bachelor of architecture or some other relevant architecture courses at all recognized institutions across India, can give NATA after their 12th examination.

NATA QUESTION PAPER PATTERN 

NATA measures drawing and observation skills, sense of proportion, aesthetic sensitivity and critical thinking ability by 2parted exams.

1. first part- paper based drawing test
2. second part- online test with MCQs on Physics, Chemistry, Mathematics and General Aptitude Test.

MATHS SYLLABUS FOR NATA

Mathematics include 

• algebra, 
• logarithm, 
• matrices, 
• trigonometry, 
• coordinate geometry, 
• 3D coordination of geometry, 
• theory of calculus, 
• application of calculus, 
• permutation and combination, 
• statistics and probability. 

MATHS AND B. ARCH

B. Arch or bachelors in Architecture is a subject where core calculations are required. To build a building one need a lots of measurements to make it proper. Architecture should know everything about how a building is being build for that they need to know the proper mathematics. They need to draw buildings first with pen and paper with all geometric calculations and measurements. 

NATA EXAM PATTERN

NATA held as a one day examination, which includes 2 parts and the duration of each part is 3 hours and total marks for the exam is out of 200.

ELIGIBILITY

• the eligibility criteria to study B. Arch, it is important to have physics, chemistry and mathematics in your 10+2 stream. So, if you are applying for NATA and don’t have Maths in your 10+2 stream then your exam is of no use. 
• Also, the maths and the questions of physics chemistry consist in NATA's paper will usually come from 10-12 standards. So, its important you know basics of both ohysics and chemistry also the mathematics very well. 

If you are thinking of giving NATA, you should check eligibility and the syllabus first and can apply frol NATA's official website. 

. 
. 
Hope this helped! 
Thank you and all the best!