# NCERT Class 9 Solutions: Heron՚s Formula (Chapter 12) Exercise 12.1 Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q-5 Sides of a triangle are in the ratio of and its perimeter is . Find its area. Solution:

• Ratio of the sides of the triangle
• Let the common ratio be then sides are
• Perimeter of the triangle
• ()
• Sides of triangle are,
• ()
• ()
• ()
• Semi perimeter of triangle (s)

Using heron՚s formula, area of the triangle

Q-6 An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle. Solution:

• Length of the equal sides
• Perimeter of the triangle
• Length of the third side
• Semi perimeter of the triangle (s)
• Using heron՚s formula, area of the triangle

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