Plz explain this:

Kindly refer the similar link for your query.
 https://www.meritnation.com/ask-answer/question/pls-explain-mid-point-theorem-used-in-the-video-above/quadrilaterals/1429931

https://www.meritnation.com/ask-answer/question/prove-that-in-a-triangle-the-line-segment-joining-the-mid-po/areas-of-parallelograms-and-triangles/9075645
Regards