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Sides of a triangle are in the ratio of 12 : 17 : 25 and its perimeter is 540cm. Find its area.

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NCERT Solutions for Class 9 Maths Chapter 12
Important NCERT Questions
Heron’s Formula
NCERT Books for Session 2022-2023
CBSE Board, UP Board and Other state Boards
EXERCISE 12.1
Page No:203
Questions No:5

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3 Answers

  1. Get Hindi Medium and English Medium NCERT Solution for Class 9 Maths to download.
    Please follow the link to visit website for first and second term exams solutions.
    https://www.tiwariacademy.com/ncert-solutions/class-9/maths/chapter-12/

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  2. Perimeter of triangle = 540 cm
    The ratio of sides of triangle = 12: 17: 25
    Let, one of the sides of triangle a = 12 x
    Therefore, remaining two sides are b = 17 x and c = 25x.
    We know that the perimeter of triangle = a + b + c
    ⇒ 540 = 12 x + 17 x + 25 x
    ⇒ 540 = 54x
    ⇒ x = 540/54 = 10
    So, the sides of triangle are a = 12 × 10 = 120 cm, b = 17 × 10 = 170 cm and c = 25 × 10 = 250 cm.
    So, the semi- perimeter of triangle is given by
    S = (a + b + c /2) = 540/2 = 270 cm
    Therefore, using Heron’s formula, the area of triangle = √s(s – a)(s – b)(s – c)
    = √270(270 – 120)(270 – 170)(270 – 250)
    = √270(150)(100)(20)
    = √81000000
    = 9000 cm²
    Hence, the area of triangle is 9000 cm².

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  3. Sides ratio: 12 : 17 : 25
    Perimeter = 540 cm → x = 10
    Sides: a = 120 cm, b = 170 cm, c = 250 cm
    Semi-perimeter (s) = 270 cm

    Area = √[s(s-a)(s-b)(s-c)]
    = √[270(150)(100)(20)]
    = √(81 × 10⁷)
    = 9000 cm²
    This question related to Chapter 10 Mathematics Class 9th NCERT. From the Chapter 10 Heron’s Formula. Probability. Give answer according to your understanding.

    For more please visit here:
    https://www.tiwariacademy.in/ncert-solutions/class-9/maths/

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