Lesson Four & Five

Class: JSS1

Subject: Mathematics

Topic: Plane Shapes


Plane Shapes are figures or shapes that are drawn on a flat or plane surfaces. Examples are square, rectangle, triangle, trapezium and circle etc.

They are also called two dimensional shapes because they are given in two directions length and breadth.

A Plane is a flat surface, such as the top of a table, playing field, wall and ceiling etc.

Classification of plane shapes

plane shapes can be classified as regular and irregular plane shapes.

Regular plane shapes are shapes with definite length and breadth; they have clear and straight edges. e.g square, rectangle etc.

Irregular plane shapes are shapes with indefinite length and breadth, their edges are crooked. e.g the shape of leaves


Identifying plane shapes


Properties of Rectangle

  1. Opposite sides are equal and parallel
  2. It has equal angle, each angle is 900
  3. The diagonal lines are equal and bisect each other
  4. It has two lines of symmetry


Properties of Square

1.All sides are equal

  1. Opposite sides are equal and parallel
  2. All angles are equal, each angle is 900
  3. The diagonal lines bisect each other at right angle ie 900
  4. It has four lines of symmetry


Classification according to their sides or lengths

Equilateral Triangle: A triangle with equal sides and equal angles.

Properties of Equilateral triangle

  1. All sides are equal
  2. It has three lines of symmetry
  3. All angles are equal; each 600

Isosceles Triangle: A triangle with two equal sides and equal base angles.

Properties of Isosceles triangle

  1. Two sides are equal
  2. Base angles are equal
  3. It has one line of symmetry

Scalene Triangle: A triangle that has no equal sides

Properties of scalene triangle

  1. None of the three sides are equal
  2. None of the three angles are equal.
  3. It has no line of symmetry.

Parallelogram: Is a four sided plane shape.

Properties of parallelogram

  1. Opposite sides are equal
  2. Opposite sides are parallel
  3. Opposite angles are equal

Trapezium: is a four sided plane shape

Properties of trapezium

  1. It one pair of parallel sides
  2. The parallel sides are not equal


Parts of circle

  1. Circumference: Is the distance round the circle.
  2. Arc: Is a portion of a circumference
  3. Diameter: Is the line that divides the circle into two equal parts and passes through the centre.
  4. Radius: Is the line from the centre of the circle to the circumference.

Properties of circle

  1. It has infinite number of lines of symmetry



              Name five things that have square shapes

  1. Measure the lengths of the diagonals of a square. What do you notice?

3.At the centre of a square, where the diagonals meet, there are four angles. What type of angles are they?

  1. How many lines of symmetry does an equilateral triangle have?
  2. What do you notice about the lines of symmetry?


N/B: Consult your Mathematics textbooks for the shape of plane shapes .

submit this assignment on the 9th June 2020 via whatsApp @ 07035773326 or in hard copy at the security post in the school.


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