Question

ABC is triangle E and F are the mid points of AB and CD respectively EFII BC, if BC=8 cm , then

find the value of EF​

Answer 1

Answer:

ANSWER

Let G be the centroid of triangle ABC. Given E and F are the mid points of BC and AC respectively. Thus, by mid point theorem, AD∥EF

AB=2EF

AD=EF (I) (D is mid point of AB)

Now, In △ADG and △GEF,

∠AGD=∠EGF (Vertically opposite angles)

AD=EF (From I)

∠ADG=∠GFE (Alternate angles for parallle lines EF and AD)

△ADG≅△EGF (ASA rule)

Thus, AG=GE (Corresponding sides)

Also, DG=GF (Corresponding sides)

Thus, AE and DF bisect each other at G.

Answer 2

Answer:

Let G be the centroid of triangle ABC. Given E and F are the mid points of BC and AC respectively. Thus, by mid point theorem, AD∥EF

AB=2EF

AD=EF (I) (D is mid point of AB)

Now, In △ADG and △GEF,

∠AGD=∠EGF (Vertically opposite angles)

AD=EF (From I)

∠ADG=∠GFE (Alternate angles for parallle lines EF and AD)

△ADG≅△EGF (ASA rule)

Thus, AG=GE (Corresponding sides)

Also, DG=GF (Corresponding sides)

Thus, AE and DF bisect each other at G.

hope this helps you