D E and F are respectively the midpoints of sides ab bc and ac of triangle ABC prove that ΔABC is similar to ΔDEF PLS ANSWER IT IS VERY URGENT?
Answers
Step-by-step explanation:
We know that line joining the mid-points of two sides of a triangle is parallel to the 3rd side.
D and F are mid-points of AB and AC respectively
Therefore, DF is parallel to BC
So, DF parallel to BE also ----------(1)
Similarly,
E and F are mid-points of BC and AC respectively,
EF is parallel to AB
Hence EF is also parallel to DB-------------(2)
From 1 & 2,
DF parallel to BE and EF is also parallel to DB
Therefore, opposite sides of a quadrilateral is parallel
DBEF is a parallelogram.
We know that, in a parallelogram opposite angles are equal.
Hence, Angle DFE = Angle ABC--------3
Similarly, We can prove that DECF is a parallelogram
In a parallelogram, opposite angles are equal
Therefore, Angle EDF = Angle ACB-----------4
Now in Triangle EDF and Triangle ABC,
Angle DFE = Angle ABC (from 3)
Angle EDF = Angle ACB (from 4)
By using AA similarity criterion Triangle DEF ~ Triangle ABC
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