Solution:
1.Let me define the term midpoint first. Mid point means that point on the line segment which divides the line segment into two equal parts.
So, Option 1 is invalid.
2. Option 2 is also invalid.why this is invalid because if S is mid point of AB, it means, SA=SB.
3. Option 3 is invalid. Two lines are parallel if ,
(a) Sum of interior angles on the same side of Transversal is 180 degree.
(b) Corresponding angles are equal.
(c) Alternate interior or exterior angles are equal.
4. Option 4 is true which is ,DE=FA,
→→if these are corresponding sides of congruent triangles, then it must be equal.
As, when triangles are congruent , their corresponding sides as well as interior angles of two triangles are equal.
