*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__

__Rectangle__

**Properties of Rectangle**

- Opposite sides are equal and parallel
- It has equal angle, each angle is 90
^{0} - The diagonal lines are equal and bisect each other
- It has two lines of symmetry

__Square__

**Properties of Square**

**1.**All sides are equal

- Opposite sides are equal and parallel
- All angles are equal, each angle is 90
^{0} - The diagonal lines bisect each other at right angle ie 90
^{0} - It has four lines of symmetry

__Triangle__

**Classification according to their sides or lengths**

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

**Properties of Equilateral triangle**

- All sides are equal
- It has three lines of symmetry
- All angles are equal; each 60
^{0}

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

**Properties of Isosceles triangle**

- Two sides are equal
- Base angles are equal
- It has one line of symmetry

** Scalene Triangle**: A triangle that has no equal sides

**Properties of scalene triangle**

- None of the three sides are equal
- None of the three angles are equal.
- It has no line of symmetry.

** Parallelogram**: Is a four sided plane shape.

**Properties of parallelogram**

- Opposite sides are equal
- Opposite sides are parallel
- Opposite angles are equal

**Trapezium**: is a four sided plane shape

**Properties of trapezium**

- It one pair of parallel sides
- The parallel sides are not equal

__Circle__

**Parts of circle**

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

**Properties of circle**

- It has infinite number of lines of symmetry

** Assignment**

** **Name five things that have square shapes

- 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?

- How many lines of symmetry does an equilateral triangle have?
- 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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