# 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