Class 9 Exam  >  Class 9 Questions  >  If one angle of a triangle is equal to the su... Start Learning for Free
If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :
  • a)
    an isosceles triangle
  • b)
    a right triangle
  • c)
    an equilateral triangle
  • d)
    an obtuse angled triangle
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
If one angle of a triangle is equal to the sum of the other two angles...
Let "a" be the measure of the angle A;
Let "b" be the measure of the angle B;
Let "c" be the measure of the angle C.
 
Then
 
a + b + c = 180,    (1)
a + b      = c.     (2)   (given).
 
Add the equation (1) and (2). You will get
 
2(a+b) + c = 180 + c.
 
Simplify:
 
2(a+b) = 180  --->  a + b = 180/2=90
View all questions of this test
Most Upvoted Answer
If one angle of a triangle is equal to the sum of the other two angles...
Explanation:

To prove that if one angle of a triangle is equal to the sum of the other two angles, then the triangle is a right triangle, we need to use the properties of the angles in a triangle.

Properties of angles in a triangle:
1. The sum of the angles in a triangle is always 180 degrees.
2. In a right triangle, one angle is equal to 90 degrees.

Proof:
Let's assume that one angle of the triangle is x degrees, and the other two angles are y and z degrees.

According to the given condition, we have the equation: x = y + z.

Since the sum of the angles in a triangle is 180 degrees, we can write another equation: x + y + z = 180.

Substituting the value of x from the first equation into the second equation, we get: y + z + y + z = 180.

Simplifying the equation, we have: 2y + 2z = 180.

Dividing both sides of the equation by 2, we get: y + z = 90.

This equation shows that the sum of the other two angles is 90 degrees. According to the properties of angles in a triangle, if the sum of two angles is 90 degrees, then the triangle is a right triangle.

Therefore, the correct answer is option 'B' - a right triangle.
Attention Class 9 Students!
To make sure you are not studying endlessly, EduRev has designed Class 9 study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Class 9.
Explore Courses for Class 9 exam

Top Courses for Class 9

If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer?
Question Description
If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? for Class 9 2024 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 9 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer?.
Solutions for If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 9. Download more important topics, notes, lectures and mock test series for Class 9 Exam by signing up for free.
Here you can find the meaning of If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice If one angle of a triangle is equal to the sum of the other two angles, then the triangle is :a)an isosceles triangleb)a right trianglec)an equilateral triangled)an obtuse angled triangleCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Class 9 tests.
Explore Courses for Class 9 exam

Top Courses for Class 9

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev