Why Area of a Trapezium : āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ āĻāĻŋāϝāĻŧ = 1/2(a + b)h
• A trapezium has only two parallel sides. : āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽāϤ āĻā§ā§ąāϞ āĻĻā§āĻāĻž āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§ āĻĨāĻžāĻā§āĨ¤
• Let the parallel sides be a and b, and h be the height. : āϧ⧰āĻž āĻšāĻāĻ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§ āĻĻā§āĻāĻž a āĻā§°ā§ b, āĻā§°ā§ h āĻšā§āĻā§ āĻāĻā§āĻāϤāĻžāĨ¤
• Take two identical trapeziums. : āĻĻā§āĻāĻž āĻāĻā§ āϧ⧰āĻŖā§° āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ āϞā§ā§ąāĻž āĻšāϝāĻŧāĨ¤
• Rotate one trapezium and join them together. : āĻāĻāĻž āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ āĻā§ā§°āĻžāĻ āĻĻā§āϝāĻŧā§āĻāĻžāĻ āĻāĻā§āϞāĻā§ āĻā§ā§°āĻž āϞāĻžāĻā§āĨ¤
• They form a parallelogram. : āĻāϝāĻŧāĻžā§° āĻĢāϞāϤ āĻāĻāĻž āϏāĻŽāĻžāύā§āϤ⧰āĻāϤā§ā§°ā§āĻā§āĻ āĻāĻ āύ āĻšāϝāĻŧāĨ¤
• Base of the parallelogram = a + b. : āϏāĻŽāĻžāύā§āϤ⧰āĻāϤā§ā§°ā§āĻā§āĻā§° āĻāĻŋāϤā§āϤāĻŋ = a + bāĨ¤
• Height of the parallelogram = h. : āϏāĻŽāĻžāύā§āϤ⧰āĻāϤā§ā§°ā§āĻā§āĻā§° āĻāĻā§āĻāϤāĻž = hāĨ¤
• Area of parallelogram = (a + b)h. : āϏāĻŽāĻžāύā§āϤ⧰āĻāϤā§ā§°ā§āĻā§āĻā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ = (a + b)hāĨ¤
• Two trapeziums together make the parallelogram. : āĻĻā§āĻāĻž āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ āĻāĻā§āϞāĻā§ āĻŽāĻŋāϞāĻŋ āĻāĻāĻž āϏāĻŽāĻžāύā§āϤ⧰āĻāϤā§ā§°ā§āĻā§āĻ āĻāĻ āύ āĻā§°ā§āĨ¤
• So, Area of one trapezium = (a + b)h ÷ 2. : āϏā§āϝāĻŧā§ āĻāĻāĻž āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ = (a + b)h ÷ 2āĨ¤
• Area depends on the average of the parallel sides multiplied by height. : āĻā§āώā§āϤā§ā§°āĻĢāϞ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§ āĻĻā§āĻāĻžā§° āĻāĻĄāĻŧ āĻā§°ā§ āĻāĻā§āĻāϤāĻžā§° āĻā§āĻŖāĻĢāϞ⧰ āĻāĻĒā§°āϤ āύāĻŋā§°ā§āĻā§° āĻā§°ā§āĨ¤
Final Formula : Area of trapezium = ½ × (sum of parallel sides) × height
āĻā§āĻĄāĻŧāĻžāύā§āϤ āϏā§āϤā§ā§°: āĻā§ā§°āĻžāĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ = ½ × (āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§ āĻĻā§āĻāĻžā§° āϝā§āĻāĻĢāϞ) × āĻāĻā§āĻāϤāĻž
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Trapezium
1. Definition | āϏāĻāĻā§āĻāĻž
A Trapezium is a quadrilateral (four-sided figure) in which one pair of opposite sides are parallel and the other two sides are not parallel.
āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ āĻšā§āĻā§ āĻāĻāĻž āĻāĻžā§°āĻŋāĻŦāĻžāĻšā§āϝā§āĻā§āϤ āĻāĻāĻžā§° (Quadrilateral) āϝ’āϤ āĻāĻāĻž āĻŦāĻŋāĻĒā§°ā§āϤ āĻŦāĻžāĻšā§ā§° āĻā§ā§°āĻž āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ (parallel) āĻĨāĻžāĻā§ āĻā§°ā§ āĻāύ āĻĻā§āĻāĻž āĻŦāĻžāĻšā§ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āύāĻšāϝāĻŧāĨ¤
2. Parts of a Trapezium | āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻ āĻāĻļāϏāĻŽā§āĻš
i. Bases (āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§) : The two parallel sides are called bases. : āĻĻā§āĻāĻž āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§āĻ Base āĻŦā§āϞāĻŋ āĻā§ā§ąāĻž āĻšāϝāĻŧāĨ¤
ii. Legs (āĻ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§) : The other two non-parallel sides are called legs. : āĻāύ āĻĻā§āĻāĻž āĻ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§āĻ Legs āĻŦā§āϞāĻŋ āĻā§ā§ąāĻž āĻšāϝāĻŧāĨ¤
iii. Height (āĻāĻā§āĻāϤāĻž) : The perpendicular distance between the two bases is called height. : āĻĻā§āĻāĻž Base ā§° āĻŽāĻžāĻāϤ āĻĨāĻāĻž āϞāĻŽā§āĻŦ āĻĻā§ā§°āϤā§āĻŦāĻ āĻāĻā§āĻāϤāĻž āĻŦā§āϞāĻŋ āĻā§ā§ąāĻž āĻšāϝāĻŧāĨ¤
iv. Diagonals (āĻā§°ā§āĻŖ) : The lines joining opposite vertices are called diagonals. : āĻŦāĻŋāĻĒā§°ā§āϤ āĻļā§ā§°ā§āώāĻŦāĻŋāύā§āĻĻā§ āϏāĻāϝā§āĻ āĻā§°āĻž ā§°ā§āĻāĻžāĻ āĻā§°ā§āĻŖ āĻŦā§āϞāĻŋ āĻā§ā§ąāĻž āĻšāϝāĻŧāĨ¤
3. Types of Trapezium | āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻĒā§ā§°āĻāĻžā§°
i. Isosceles Trapezium (āϏāĻŽāĻĻā§āĻŦāĻŋāĻŦāĻžāĻšā§ āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ) : In this trapezium, the two legs are equal in length and the base angles are also equal. : āĻāĻ āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽāϤ āĻĻā§āĻāĻž āĻ āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻŦāĻžāĻšā§ āϏāĻŽāĻžāύ āĻšāϝāĻŧ āĻā§°ā§ Base ā§° āĻā§āĻŖāϏāĻŽā§āĻšā§ āϏāĻŽāĻžāύ āĻšāϝāĻŧāĨ¤
ii. Right Trapezium (āϏāĻŽāĻā§āĻŖā§ āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ) : One of the legs is perpendicular to the base and it contains a right angle (90°). : āĻāĻāĻž āĻŦāĻžāĻšā§ Base ā§° āϏā§āϤ⧠āϞāĻŽā§āĻŦ āĻšāϝāĻŧ āĻā§°ā§ āĻāϝāĻŧāĻžāϤ ⧝ā§Ļ° āϏāĻŽāĻā§āĻŖ āĻĨāĻžāĻā§āĨ¤
iii. Scalene Trapezium (āĻ āϏāĻŽāĻŦāĻžāĻšā§ āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽ) : All sides and angles are different in this trapezium. : āĻāĻ āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽāϤ āϏāĻāϞ⧠āĻŦāĻžāĻšā§ āĻā§°ā§ āĻā§āĻŖ āĻ āϏāĻŽāĻžāύ āĻšāϝāĻŧāĨ¤
4. Properties of Trapezium | āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻā§āĻŖāĻžāĻŦāϞā§
i. A trapezium has four sides and four angles. : āĻāĻāĻž āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽāϤ ā§ĒāĻāĻž āĻŦāĻžāĻšā§ āĻā§°ā§ ā§ĒāĻāĻž āĻā§āĻŖ āĻĨāĻžāĻā§āĨ¤
ii. One pair of opposite sides are parallel. : āĻāĻāĻž āĻŦāĻŋāĻĒā§°ā§āϤ āĻŦāĻžāĻšā§ā§° āĻā§ā§°āĻž āϏāĻŽāĻžāύā§āϤ⧰āĻžāϞ āĻšāϝāĻŧāĨ¤
iii. The sum of all interior angles is 360°. : āĻāĻŋāϤ⧰⧰ āϏāĻāϞ⧠āĻā§āĻŖā§° āϝā§āĻāĻĢāϞ ā§Šā§Ŧā§Ļ°āĨ¤
iv. The diagonals intersect each other inside the trapezium. : āĻā§°ā§āĻŖ āĻĻā§āĻāĻž āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻāĻŋāϤ⧰āϤ āĻāĻā§ āĻ āĻžāĻāϤ āĻā§āĻĻ āĻā§°ā§āĨ¤
5. Area of a Trapezium | āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻā§āώā§āϤā§ā§°āĻĢāϞ
Formula (āϏā§āϤā§ā§°): Area = ½ × (a + b) × h
Here a and b are the bases and h is the height. : āĻāϝāĻŧāĻžāϤ a āĻā§°ā§ b āĻšā§āĻā§ base āĻā§°ā§ h āĻšā§āĻā§ āĻāĻā§āĻāϤāĻžāĨ¤
Example (āĻāĻĻāĻžāĻšā§°āĻŖ): If the bases are 6 cm and 10 cm and the height is 5 cm, Area = ½ × (6 + 10) × 5 = 40 cm² : āϝāĻĻāĻŋ Base āĻĻā§āĻāĻž ā§Ŧ āϏā§āĻŽāĻŋ āĻā§°ā§ ā§§ā§Ļ āϏā§āĻŽāĻŋ āĻā§°ā§ āĻāĻā§āĻāϤāĻž ā§Ģ āϏā§āĻŽāĻŋ, āϤā§āύā§āϤ⧠āĻā§āώā§āϤā§ā§°āĻĢāϞ = ā§Ēā§Ļ āĻŦā§°ā§āĻ āϏā§āĻŽāĻŋāĨ¤
6. Perimeter of Trapezium | āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻĒā§°āĻŋāϏā§āĻŽāĻž
The perimeter of a trapezium is the sum of all four sides : āĻā§ā§°ā§āĻĒāĻŋāĻāĻŋāϝāĻŧāĻžāĻŽā§° āĻĒā§°āĻŋāϏā§āĻŽāĻž āĻšā§āĻā§ āĻāĻžā§°āĻŋāĻāĻž āĻŦāĻžāĻšā§ā§° āĻŽā§āĻ āϝā§āĻāĻĢāϞāĨ¤. Perimeter = a + b + c + d