Home
Class 9
MATHS
In Figure, D ,E and F are, respectively ...

In Figure, `D ,E` and `F` are, respectively the mid-points of sides `B C ,C A` and `A B` of an equilateral triangle `A B C` . Prove that `D E F` is also an equilateral triangle.

Text Solution

Verified by Experts


`"Proof: As ABC is an equilateral triangle
`therefore AB=BC=AC`-(1)
By midpoint theorem:
`EF=1/2 BC `
`DF=1/2 AC`
`DE=1/2 AB`
`therefore 1/2 AB=1/2 AC=1/2 BC`
`therefore EF=DF=ED`
...
Promotional Banner

Topper's Solved these Questions

  • PROBABILITY

    RD SHARMA|Exercise All Questions|67 Videos
  • RATIONALISATION

    RD SHARMA|Exercise All Questions|130 Videos

Similar Questions

Explore conceptually related problems

If D,E and F are respectively the midpoints of the sides BC,CA and AB of an equilateral triangle ABC ,prove that /_DEF is also an equilateral triangle.

D, E and F are the mid-points of the sides BC, CA and AB, respectively of and equilateral Delta ABC. Show that Delta DEF is also an equilateral triangle.

In the adjoining figure D, E and F are the mid-points of the sides BC, CA and AB of the equilateral DeltaABC. Prove that DeltaDEF is also an equilateral triangle.

If D, E and F are the mid-points of the sides of an equilateral triangle ABC, then the ratio of the area of triangle DEF and DCF is :

E , F , G , H are respectively, the mid-points of the sides A B ,B C ,C D and D A of parallelogram A B C D . Show that the quadrilateral E F G H is a parallelogram and that its area is half the area of the parallelogram, A B C Ddot GIVEN : A quadrilateral A B C D in which L ,F ,G ,H are respectively the mid-points of the sides A B ,B C ,C D and D Adot TO PROVE : (i) Quadrilateral E F G H is a parallelogram a r(^(gm)E F G H)=1/2a r(^(gm)A B C D) CONSTRUCTION : Join A C and H F

If D ,E ,F are the mid-points of the sides B C ,C Aa n dA B respectively of a triangle A B C , prove by vector method that A r e aof D E F=1/4(a r e aof A B C)dot

In DeltaA B C , D, E and F are respectively the mid-points of sides AB, BC and CA. Show that DeltaA B C is divided into four congruent triangles by joining D, E and F.

In the adjoining figure D, E and F are the mid-points of the sides BC, AC and AB respectively. triangle DEF is congruent to triangle :

D ,\ E ,\ F are the mid-points of the sides B C ,\ C A and A B respectively of a A B C . Determine the ratio of the areas of D E F and A B C .

RD SHARMA-QUADRILATERALS-All Questions
  1. ABC is a triangle right angled at C. A line through the mid-point M ...

    Text Solution

    |

  2. The line drawn through the mid-point of one side of a triangle, para...

    Text Solution

    |

  3. In Figure, D ,E and F are, respectively the mid-points of sides B C ,C...

    Text Solution

    |

  4. In DeltaA B C , D, E and F are respectively the mid-points of sides ...

    Text Solution

    |

  5. l, m and n are three parallel lines intersected by transversals p an...

    Text Solution

    |

  6. A B C D is a square E , F , G and H are points on AB , BC , CD and D A...

    Text Solution

    |

  7. A B C D is a rhombus, E A B F is a straight line such that E A=A B=B F...

    Text Solution

    |

  8. A B C D is a parallelogram. A D is a produced to E so that D E=D C and...

    Text Solution

    |

  9. The line segment joining the mid-points of any two sides of a triangle...

    Text Solution

    |

  10. In a quadrilateral ABCD, CO and DO are the bisectors of /C and /D resp...

    Text Solution

    |

  11. The angle of a quadrilateral are respectively 100^@, 98^@, 92^ Find th...

    Text Solution

    |

  12. In a quadrilateral ABCD , the angles A , B , C and D are in the ratio ...

    Text Solution

    |

  13. The sides B A and D C of a quadrilateral A B C D are produced as shown...

    Text Solution

    |

  14. In a quadrilateral A B C D ,A O and B O are the bisectors of /A and /B...

    Text Solution

    |

  15. In Figure, bisectors of /B and /D of quadrilateral A B C D meet C D an...

    Text Solution

    |

  16. The angle of a quadrilateral are respectively 100^@, 98^@, 92^@ Find t...

    Text Solution

    |

  17. In a quadrilateral ABCD , the angles A , B , C and D are in the ratio ...

    Text Solution

    |

  18. In a quadrilateral ABCD ,CO and DO are the bisectors of /C and /D resp...

    Text Solution

    |

  19. The angles of a quadrilateral are in the ratio 3:5:9: 13. Find all the...

    Text Solution

    |

  20. In a parallelogram ABCD , prove that sum of any two consecutive angl...

    Text Solution

    |