The area of a triangle is 486 cm2 and its sides are in the ratio 3 : 4 : 5. The perimeter of the triangle is:
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Correct answer: A
Explanation
The correct answer is option 1 i.e. 108 cm.
Let the sides of the triangle be 3x, 4x and 5x.
Since the given sides are triplets, the triangle is a right angled triangle.
Area of right angled triangle = ½ × b × h
According to the given question,
Area of triangle = 486
⇒ ½ × b × h = 486
⇒ ½ × 3x × 4x = 486
⇒ x2 = 81
⇒ x = 9
Now, perimeter of given triangle = 3x + 4x + 5x
⇒ 12x = 12 × 9 = 108 cm
Hence the perimeter of the triangle is 108 cm.