maths solution class 7 perimeter and area EX:11.3
It's better to do yourself but If you found any problems you can ask your teachers
There are many websites which can provide you with the solutions of maths ncert online. You have not mentioned the question number so I suppose the require the solutions to the complete exercise. I could provide you with a link to any website but I guess you too could do that using google. But maths is a subject which you should practice more and more so I would suggest try to look and understand the solved questions first and the solve the unsolved exercises. Even then if you face any problem in any particular question or concept, feel free to ask.