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Everyone already knows how to find the area of a triangle using the general formula or the specific formula for an Equilateral triangle. But have you ever wondered how we can get the area of a triangle when it is a scalene triangle, which means the length of all three sides is different, and you have no clue how to get the altitude? In such cases, Heron’s formula becomes a lifesaver, helping us find the triangle's area. In Class 9 Maths Chapter 10 solutions, students will learn about Heron’s formula, also known as the Heron’s formula. Heron’s formulas have many real-life examples, and they help calculate the area of irregular plots. The NCERT Solutions for this chapter simplify the process through practical questions and straightforward explanations.
The concept of Heron’s formula is not only important for class 9 board exams but also for higher-level and competitive exams. These Heron’s formula class 9 NCERT solutions follow the latest CBSE guidelines and have been prepared by Careers360 teachers who have multiple years of experience in this field. Students can try to solve the exercises of the NCERT textbooks on their own before checking these well-structured solutions of Heron’s formula class 9. The latest NCERT Solutions for Class 9 Maths covers various triangle types and extends the concept to real-world problems involving quadrilaterals. Along with this, the NCERT Solutions for Class 9 materials help students apply the formula accurately, especially when dealing with application-based or word problems in exams.
Triangle:
Semi-perimeter of a triangle
Where 's' is the semi-perimeter, and 'a', 'b', and 'c' are the lengths of its sides.
Area
Equilateral Triangle:
For an equilateral triangle with side length 'a':
Its perimeter is given by: Perimeter = 3a units.
The altitude (height) of an equilateral triangle is equal to
The area of an equilateral triangle is equal to
Class 9 Maths chapter 12 Question Answer: Exercise: 12.1 |
Answer:
Given: The Perimeter of the equilateral triangle is 180 cm.
Therefore, each side of the triangle is:
a =
Now, calculate the semi-perimeter:
s =
Use Heron’s Formula to find the area, that is:
Area =
Thus,
Area =
Area =
Answer:
From the figure,
Let the sides of the triangle be:
a = 122m, b = 120m and c = 22m
Therefore, the semi-perimeter,
Thus, Area ( using Heron’s formula ):
Given the rent for 1 year (i.e., 12 months) per square meter is Rs. 5000.
Thus, rent for 3 months per square meter will be:
Therefore, for 3 months for 1320 m2:
Answer:
We are given the sides of the triangle, which are:
a = 15 m, b = 11m and c = 6m
So, the semi-perimeter of the triangle will be:
Therefore, the area painted in colour is:
Question 4: Find the area of a triangle, two sides of which are 18 cm and 10 cm, and the perimeter is 42 cm.
Answer:
Given the perimeter of the triangle is 42cm and the lengths of two sides, a = 18 cm and b = 10 cm.
So,
Or,
Thus, the semi-perimeter of the triangle will be:
Therefore, the area given by the Heron's Formula will be,
Question 5: Sides of a triangle are in the ratio of 12 : 17 : 25, and its perimeter is 540 cm. Find its area.
Answer:
Given the sides of a triangle are in the ratio of 12 : 17 : 25 and its perimeter is 540 cm.
Let, the length of one side of the triangle to be
Then, the remaining two sides be
Thus, by the given perimeter,
Perimeter = a + b + c = 12x + 17x + 25x = 540cm
Therefore, the sides of the triangle are:
The semi-perimeter of the triangle is:
Therefore, using Heron's Formula, the area of the triangle is:
Answer:
Given, the perimeter of an isosceles triangle is 30 cm and the length of the sides which are equal is 12 cm.
Let the third side length be 'a cm'.
Then,
So, the semi-perimeter of the triangle is:
Therefore, using Heron's Formula, the area of the triangle is:
Question: Find the area of a triangle whose sides are 9 cm, 10 cm, and 17 cm using Heron’s formula.
Answer:
Let the sides be a = 9 cm, b = 10 cm, c = 17 cm
1. Memorise the Heron’s Formula: Students need to remember the standard formula, which states Area equals the square root of semi-perimeter times its difference with each side. The formula uses
2. Calculate semi-perimeter accurately: The calculation of
3. Check if a triangle is valid: The triangle inequality rule should be used to verify triangle feasibility before you implement the formula.
4. Work with different triangle types: Apply Heron’s formula on various triangle shapes, including scalene, isosceles and right-angled to enhance your understanding of the concept.
5. Special attention must be given when simplifying square roots: Preparing the value inside the square root for calculation before extracting the root will reduce errors, particularly when working with irrational numbers.
6. Extend to real-world problems: When solving problems about land plots or uneven quadrilaterals, apply Heron’s rule by dividing the shape into two triangles.
Students can also check these subject-wise solutions. These solutions have explained every step and are written in very easy language.
The following links can be used to find the latest CBSE syllabus and a reference math book. These are very useful study materials to do well in the exam.
Area of a Triangle – by Heron’s Formula and Application of Heron’s Formula in finding Areas of Quadrilaterals are two important topics of this chapter. Students can prioritize important topics from the NCERT syllabus and study accordingly to score well in exams. for ease you can study heron's formula class 9 pdf both online and offline mode.
Here are the rephrased key benefits of NCERT Solutions for Class 9 Maths Chapter 12:
The solutions for each exercise within the chapter are easily accessible for students to refer to.
The solutions are designed with graphs and illustrations that aid in providing a clear understanding of the mathematical concepts.
The solutions are meticulously prepared by the expert team at Careers360, with a strong emphasis on accuracy.
NCERT solutions are helpful for the students if they are no able to solve NCERT problems on their own. Also, these solutions are provided in a very detailed manner which will give them conceptual clarity.
Here you will get the detailed NCERT solutions for class 9 maths by clicking on the link. Practicing these solutions will give you in-depth understanding of concepts which help you to score good marks in the exam.
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