The area of a triangle is 216 cm² and its sides are

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The area of a triangle is 216 cm² and its sides are in the ratio 3 : 4 : 5. The perimeter of the triangle is :

Using Rule 1,
Let the sides be 3x, 4x and 5x respectively.
Here, (3x)² + (4x)² = (5x)²
Hence, the triangle is right angled.

∴	1	× 3x × 4x = 216
	2

⇒ 6x² = 216 ⇒ x²

	216	= 36
	6

∴ x = 36 = 6
Perimeter of triangle = (3x + 4x + 5x) cm
= 12x cm = 12 × 6 = 72 cm