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2D Mensuration: Introduction
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This is introductory lesson of the 2D figure mensuration. This lesson highlights the formula of different 2D figures of area and perimeter.

Manish Pandey
I am an engineer, educator at unacademy, aspire to be a government officer. Love to play badminton , watch football ,cook and eat.

Unacademy user
Sir,hame S P Bakshi se samajh nahi as raha hai ki kaise study kare thoda difficult lag raha hai uske rules baki books ke rule se different hai please help me
Small correction needed on slide no 3 for perimeter of parallelogram.
Manish Pandey
2 years ago
yess !! i have mistyped + as x !! the perimeter of parallelogram = 2(a+b)
  1. ABOUT ME Manish Pandey Electrical Engineer . Work as Educator at Unacademy Follow me on unacademy If you like the lesson review and rate it and drop any query regarding the related course I'll answer that definitely.

  2. Mensuration -20 Area is the amount of 2-D space taken by an object. . The length of border around any 2-D object is called perimeter. . In this course we will learn about area of different 2-D shapes. .Questions are often asked from this topic.

  3. Quadrilateral .Parallelogram |Area = Base height = b h 2 Perimeter = 2(a b) .Rhombus 2. Perimeter = 4a Rectangle 1, Area = 1 b 2. Perimeter = 2(1 + b) * Square 1. Area = a2 2. Perimeter = 4a . Trapezium Area-asum of parallel sides height =-(a + b) h

  4. Triangle Heron's formula Area = Vs(s-a) (s-b) (s-c) where, s = a+b+c Area of right angled triangle 1 Area = base height =- b h 2

  5. Circle Area of circle A = 2 Area of sector A =- . Tr2 360 Circumference of circle C = 2 r Circumference of sector C- 2 360

  6. Points to Remember When problems related related to fencing or making boundary are considered, then rate is multiplied by perimeter . When problems related grazing, tiling and painting are considered area is multiplied by the given rate.