Basic proportionality Theorem or Thales Theorem - If a line is drawn parallel to one side of a triangle intersecting the other two sides; then it divides the two sides in the same ratio.

Theorem 6.1 : If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, the other two sides are divided in the same ratio.

'If a line is drawn to one side of a triangle to intersect the other two sides in distinct points, prove that the other two sides are divided in the same ratio.

Prove that , "If a line parallel to a side of a triangle intersects the remaining sides in two distinct points then the line divides the sides in the same proportion".

Prove that, if a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, the other two sides are divided in the same ratio. Using the above result, do the following: In Fig. 7 .45 DE abs() BC and BD = CE. Prove that DeltaABC is an isosceles triangle.

Thales theorem is given by a greek mathematician. According to this theorem, if a line is drawn parallel to one side of a triangle then it divides the other two sides in the same ratio. This theorem is also known as Basic Proportionality Theorem. Here, the value of x is :

If a line is drawn parallel to one side of a triangle to intersect the other two sides in disinct points, the other two sides are divided in the same ratio. Using this theoure. Find EC in if DE||BC.

Theorem 6.2 : If a line divides any two sides of a triangle in the same ratio, then the line is parallel to the third side.

The line drawn from the midpoint of one side of a triangle parallel to another side bisects the third side.