An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. find the area of the triangle.

Transcript Ex 10.1, 6 An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle. Area of triangle = (s(s a)(s b)(s c)) Here, s is the semi-perimeter, and a, b, c are the sides of the triangle Given triangle is isosceles In isosceles triangle, two sides are equal So, a = b = 12 cm and Perimeter = 30 cm Semi-Perimeter = s =Perimeter/2 s = 30/2 s = 15 cm We need to find c Perimeter = 30cm a + b + c = 30 cm 12 cm+ 12 cm + c = 30 cm 24 + c = 30 c = 30 24 c = 6 cm Area of triangle = ( ( )( )( )) Putting a = 12 cm, b =12 cm, c = 6 cm & s = 15 cm = (15(15 12)(15 12)(15 6)) = (15(3)(3)(9)) = (15 (9)(9)) = ("9" 9) 15 = ("92" ) 15 = (9) 15 = 9 15 Thus, Area = 9 15 cm2 Show More

Let the third side of this triangle be x. Perimeter of triangle =30 cm 12 cm +12 cm + x = 30 cm ∵ Isosceles triangle So, x = 6 cm s = P e r i m e t e r o f t r i a n g l e 2 = 30 c m 2 = 15 c m By H er on ’s form u la, Area of given triangle = √ s ( s − a ) ( s − b ) ( s − c ) = √ 15 ( 15 − 12 ) ( 15 − 12 ) ( 15 − 6 ) c m 2 = √ 15 ( 3 ) ( 3 ) ( 9 ) c m 2 = 9 √ 15 c m 2

NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula Ex 12.1 are part of NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula Ex 12.1 Ex 12.1 Class 9 Maths Question 1. A traffic signal board, indicating ‘SCHOOL AHEAD’, is an equilateral triangle with side a. Find the area of the signal board, using Heron’s formula.If its perimeter is 180 cm, what will be the area of the signal board? Solution: Let each side of the equilateral triangle be a. Semi-perimeter of the triangle, Ex 12.1 Class 9 Maths Question 2. The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m and 120 m (see figure). The advertisements yield an earning of ₹5000 per m² per year. A company hired one of its walls for 3 months. How much rent did it pay? Solution: Let the sides of the triangular will be a = 122m, b = 12cm, c = 22m Semi-perimeter, s = \(\frac \)) = (2 x 56) m 2 = 112 m 2 So, area of the field = area of ∆BCE + area of parallelogram ABED = 84 m 2 + 112 m 2 = 196 m 2 NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula (हीरोन सूत्र) (Hindi Medium) Ex 12.1 NCERT Solutions for Class 9 Maths • • • • • • • • • • • • • • • • We hope the NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula Ex 12.1 help you. If you have any query regarding NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula Ex 12.1, drop a comment below and we will get back to you at the earliest.

An isosceles triangle has perimeter 31 cm and each of the equal sides is 12 cm. Find the area of the triangle. Isosceles Triangle: In reference to the plane geometry, the basic characteristic of an isosceles triangle is that the length of the two slant sides of an isosceles triangle will always be the same but the length of the third side will differ. The isosceles triangle looks like a pyramid in two dimensions. Answer and Explanation: 1