Since $\triangle ABD$ and $\triangle ACD$ have equal area, you may wonder — Can we divide $\triangle ABD$ using straight cuts into two or more pieces that we can then rearrange to exactly cover $\triangle ACD$? Is it possible?        [Page No. 133]

Yes, it is possible. The two triangles are formed by the median AD, so they have equal areas. They share the side AD, have equal bases (BD = DC), and the same height (the perpendicular distance from A to the line BC). Because the two triangles have equal base and equal height, they are equal in area. By making suitable straight cuts in one triangle and rearranging the resulting pieces, we can fit them exactly onto the other triangle without changing the total area.

One way to think about this is that if one triangle is 'slid' along the line BC, its shape changes position but its base and height remain the same. Through a suitable cutting and rearranging process, the pieces of $\triangle A B D$ can therefore be reassembled to form $\triangle A C D$.