# NCERT Class 9 Solutions: Heron's Formula (Chapter 12) Exercise 12.1 Part 2

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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