Home
Class 7
MATHS
In a Delta ABC, if the bisector of the a...

In a `Delta ABC`, if the bisector of the angle BAC meets BC in D, then which one of the following is correct?

A

`AB le BD`

B

`angle DBA gt (1)/(2) angle BAC`

C

`Delta ABD` can never be isosceles

D

If `BD = AD`, then `Delta ABD` will be equilateral.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the triangle \( \Delta ABC \) where the angle bisector of \( \angle BAC \) meets side \( BC \) at point \( D \). We want to determine which statement about the angles in this triangle is correct. ### Step-by-Step Solution: 1. **Identify the Given Information**: - We have triangle \( ABC \). - The angle bisector \( AD \) of \( \angle BAC \) meets side \( BC \) at point \( D \). 2. **Understand the Angle Bisector**: - Since \( AD \) is the angle bisector, it divides \( \angle BAC \) into two equal parts: \[ \angle DAC = \angle DAB = \frac{1}{2} \angle BAC \] 3. **Consider the Exterior Angle**: - The exterior angle at vertex \( D \) (formed by extending side \( BC \) beyond point \( D \)) is given by: \[ \angle BDA = \angle DAB + \angle ABC \] - This means that \( \angle BDA \) is equal to the sum of \( \angle DAB \) and \( \angle ABC \). 4. **Apply the Exterior Angle Theorem**: - According to the exterior angle theorem, the exterior angle \( \angle BDA \) is greater than either of the opposite interior angles \( \angle DAC \) or \( \angle ABC \): \[ \angle BDA > \angle DAC \] 5. **Substituting the Values**: - Since \( \angle DAC = \frac{1}{2} \angle BAC \), we can express the relationship: \[ \angle BDA > \frac{1}{2} \angle BAC \] 6. **Conclusion**: - Therefore, we can conclude that: \[ \angle BDA > \frac{1}{2} \angle BAC \] - Among the options provided, the correct statement is that \( \angle BAD \) (which is equal to \( \angle DAB \)) is greater than \( \frac{1}{2} \angle BAC \). ### Final Answer: The correct statement is that \( \angle BAD > \frac{1}{2} \angle BAC \).
Promotional Banner

Topper's Solved these Questions

  • TRIANGLES

    S CHAND IIT JEE FOUNDATION|Exercise Question Bank- 18|24 Videos
  • TRIANGLES

    S CHAND IIT JEE FOUNDATION|Exercise Self Assessment Sheet - 18|10 Videos
  • TIME AND WORK

    S CHAND IIT JEE FOUNDATION|Exercise Self Assessment Sheet - 13|15 Videos
  • VOLUME AND SURFACE AREA OF A CUBE AND A CUBOID

    S CHAND IIT JEE FOUNDATION|Exercise UNIT TEST - 5|20 Videos

Similar Questions

Explore conceptually related problems

Let the bisector of the angle BAC of a triangle ABC meet BC in X. Which one of the following is correct?

In a triangle ABC if the angles A, B, C are in AP, then which one of the following is correct ?

In a Delta ABC,AD is the bisector of the angle A meeting BC at D.If I is the in centre of the triangle,then AI:DI is equal to

The median BD of the triangle ABC meets AC at D. If BD = 1/2AC , then which one of the following is correct ?

In a triangle ABC, internal bisector of angleABC and external bisector of angleACB meet in D. Which one of the following is true ?

If median of the Delta ABC through A is perpendicular to BC, then which one of the following is correct ?

A(3,2,0),B(5,3,2) and C(-9,6,-3) are the vertices of a triangle ABC if bisector of angle BAC meets BC at D, then co- ordinates of D are

The side BC of a triangle ABC is produced to D, bisector of the angle ABC and ACD meet at P. If angleBPC =x^(@) and angleBAC = y^(@) , then which one of the following is correct ?

In a triangle ABC, AD is perpendicular on BC. If angle BAC = 90^(@), AB = c, BC = a, CA = b and AD = p, then which one of the following is correct?