Geometry and Shapes 

Geometry is useful in recognizing the shapes. Do you want to know the shape of` your house, toys and favorite chocolate?



Let Us Revise Few Shapes


Maths class 4 Fractions


Now we will study the shapes formed with the help of sleeping lines, slanting lines, curved lines!


Maths class 4 Fractions



Maths class 4 Fractions




Angle is the figure formed by two rays, called sides of angle. Both sides have common end point, called vertex of the angle.

Maths class 4 Fractions



  • A positive angle goes anti-clockwise.
  • A negative angle goes clockwise.


Type of Angles


Sr No

Angle Type



Acute Angle

An angle less than 90°


Right Angle

An angle that is equal to 90°


Obtuse Angle

An angle greater than 90° but less than 180°


Straight Angle

An angle equals to 180°


Reflex Angle

An angle greater than 180°


Maths class 4 Fractions




A circle is the locus of all the points that are equidistant from central point.


  • Radius of Circle: It is the distance from the center to the edge.


  • Diameter: It starts from one end of the circle and ends on another while going through center.

Formula: Diameter = 2×Radius

  • Circumference: It is the distance around the edge of circle.

Formula: Circumference = 2×Π×Radius

  • Area of Circle: The area of circle is Π times the radius squared.


Formula: Area =Π×Radius²


Maths class 4 Fractions


Example 1: A circle has radius 50 cm. Calculate its circumference.


Sol: Diameter = 2×50 = 100 cm

Circumference = Π×100 = 314 cm


Example 2: Find the area of circle having radius 2 m?


Sol: Area = Π×R² = 3.14×2×2 = 3.14×4 = 12.56 m²


Practice These Questions


  • Find out the number of sleeping lines, slanting lines, curved lines, circles, square, triangle and rectangle in the figure below:


Maths class 4 Fractions



  • Name the angles:
  1. 78°
  2. 156°
  • 45°
  1. 255°
  2. 180°


  • Find out the diameter, circumference and area of circle whose radius is 20 cm?



  • Ray is extended to one end only.
  • Line is extended towards both ends.
  • Line segment is a part of line with two end points.
  • Angle less than 90° is acute angle; angle more than 90° is obtuse angle.
  • 90°angle is called right angle.
  • Radius of circle is half of its diameter.