D, E and F are respectively the mid points
of the sides AB, BC and CA of triangle ABC
respectively. Find the ratio of areas of trian
DEF and triangle ABC.
Answers
Answered by
1
Answer
Given: In ΔABC, D,E and F are midpoints of sides AB,BC and CA respectively.
BC=EC
Recall that the line joining the midpoints of two sides of a triangle is parallel to third side and half of it.
Therefore,we have:
DF=d 1/2 BC
----- DF/BC=1/2 -------(1)
DE/AC=1/2 ----------(2) and
EF/AB=1/2 ----------(3)
From (1), (2) and (3) we have
But if in two triangles, sides of one triangle are proportional to the sides of the other triangle, then their corresponding angles are equal and hence the two triangles are similar
Therefore, ΔABC∼ΔEDF [By SSS similarity theorem]
Hence area of ΔABC: area of ΔDEF=4:1
Similar questions