Back to: MATHEMATICS JSS1

**Welcome to class! **

In today’s class, we will be talking more about geometry plane shapes. Enjoy the class!

**GEOMETRY PLANE SHAPES **

The perimeter of a regular polygon, square, rectangle, triangle, trapezium, parallelogram, and circle Area of plain shapes such as square, rectangle, triangle, trapezium, parallelogram, and circle

*The different geometrical shapes formula of area and perimeter with examples are discussed below:*

**Perimeter and Area of Rectangle:**

● The perimeter of rectangle = 2(l + b).

- Area of rectangle = l × b;
*(l and b are the length and breadth of the rectangle)* - Diagonal of rectangle = √ (l² + b²)

**Perimeter and Area of the Square:**

- The perimeter of square = 4 × S.
- Area of square = S × S.
- Diagonal of square = S√2;
*(S is the side of the square)*

**Perimeter and Area of the Triangle:**

- Perimeter of triangle = (a + b + c);
*(a, b, c is 3 sides of a triangle)* - Area of triangle = √ (s (s – a) (s – b) (s – c)); where
*s is the semi-perimeter of triangle* - S = 1/2 (a + b + c)
- Area of triangle = 1/2 × b × h;
*(b base, h height)* - Area of an equilateral triangle = (a²√3)/4;
*(a is the side of the triangle)*

**Perimeter and Area of the Parallelogram:**

- The perimeter of parallelogram = 2 (sum of adjacent sides)
- Area of parallelogram = base × height

**Perimeter and Area of the Rhombus:**

- Area of rhombus = base × height
- Area of rhombus = 1/2 × length of one diagonal × length of other diagonal
- The perimeter of rhombus = 4 × side

**Perimeter and Area of the Trapezium:**

- Area of trapezium = 1/2 (sum of parallel sides) × (perpendicular distance between them)

= 1/2 (p₁ + p₂) × h (p₁, p₂ are 2 parallel sides)

**Circumference and Area of Circle:**

- Circumference of circle = 2πr

= πd

**Where**, π = 3.14 or π = 22/7

r is the radius of the circle

d is the diameter of the circle

● Area of circle = πr²

● Area of ring = Area of the outer circle – Area of the inner circle.

In our next class, we will be talking about **Three Dimensional Shapes**. We hope you enjoyed the class.

Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.

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