Video Transcript
In the figure below, given that π΄π΅πΆπ· is a rectangle, ππ΅πΆπ» is a parallelogram, and π΄π equals 3.7 centimetres, find the length of π»π΄.
Letβs start by adding in the information that π΄π is 3.7 centimetres. We can then also establish that the length π»π΄ is the line coloured in orange. Letβs see if we can use any of the facts we know about parallelograms or rectangles to help us work out this missing length.
We can recall that the opposite sides of a parallelogram are parallel and congruent, where congruent means the same length. This means that our line segment π΅πΆ, which is 11.8 centimetres, is parallel to our line segment ππ». And since itβs congruent, this means that ππ» is 11.8 centimetres.
So to find our line segment π»π΄, we can take the longer line segment of ππ» and subtract the line segment π΄π. Therefore, π»π΄ is equal to 11.8 subtract 3.7, giving us 8.1 centimetres for the length of line segment π»π΄.
