Question Video: Using the Properties of Parallelograms to Find Missing Lengths Mathematics

Video Transcript

Find the lengths of line segment 𝐶𝐷 and line segment 𝐷𝐴.

If we look at this quadrilateral 𝐴𝐵𝐶𝐷, the first thing we can do is identify that this is a parallelogram. This is because we can see on the diagram that we have opposite sides parallel. If we use the properties of a parallelogram, we can recall that it’s not just simply that opposite sides are parallel, but opposite sides are equal in length too. The line segment 𝐶𝐷 is opposite to the line segment 𝐴𝐵. So 𝐶𝐷 will be 15 centimeters. Next, we need to find the length of the line segment 𝐷𝐴. And it is opposite to the line segment 𝐶𝐵. As these two line segments are the same length, then 𝐷𝐴 will also be 13 centimeters.

And so we can give the answer for the two line segments as 𝐶𝐷 is equal to 15 centimeters and 𝐷𝐴 is equal to 13 centimeters.