### Video Transcript

π΄π΅πΆπ· is a parallelogram in
which the measure of angle π΅πΈπΆ equals 79 degrees and the measure of angle
πΈπΆπ΅ equals 56 degrees. Determine the measure of angle
πΈπ΄π·.

In this figure, we can see that
we have the two angles π΅πΈπΆ and πΈπΆπ΅ given. And we need to determine the
measure of angle πΈπ΄π·. As we are told that this is a
parallelogram, then that means that we can apply the properties of
parallelograms to help us find this unknown angle. And as we are thinking about an
angle, then the two angle properties of a parallelogram are that opposite angles
are equal in measure and the sum of the measures of two consecutive angles is
180 degrees. As we want to find the measure
of angle πΈπ΄π·, then a consecutive angle which might be useful to know is the
measure of angle πΆπ΅πΈ. If we knew this, then by the
second property here we could calculate the measure of angle πΈπ΄π·.

Letβs consider this triangle
π΅πΈπΆ. As we are given two angles, we
can apply the property that the interior angle measures in a triangle sum to 180
degrees. This means that the measure of
angle πΆπ΅πΈ plus 56 degrees plus 79 degrees is equal to 180 degrees. Rearranging this, we obtain
that the measure of angle πΆπ΅πΈ is equal to 180 degrees subtract 135 degrees,
and that is 45 degrees. And then as previously
mentioned, we can identify this pair of consecutive angles. The measure of angle πΈπ΄π· and
the measure of angle πΆπ΅πΈ must add to be 180 degrees. To find the measure of angle
πΈπ΄π· then, we subtract 45 degrees from 180 degrees, giving us an answer of 135
degrees.