### Video Transcript

Given that π΄π΅πΆπ· is a parallelogram, find the area of triangle π΄π΅π.

So, here, weβre given this parallelogram π΄π΅πΆπ·. And we need to find the area of this triangle π΄π΅π. In order to do this, weβll need to recall a fact about parallelograms. And that is that a parallelogram has two pairs of parallel and congruent sides. So therefore, the line πΆπ· is parallel and equal in length to the line π΄π΅. In the same way, the other two sides β that is, π΄π· and πΆπ΅ β are equal and parallel. We could then write that the length π΄π· must also be 20 centimeters.

In order to find this length of π΄π, we observe the demarcations on the lines here at ππ· and π΄π, which means that these lengths are the same size. This means that our 20-centimeter length of π΄π· must be split into two equal sections of 10 centimeters each.

To find the area of π΄π΅π, weβll need to recall the formula for the area of a triangle. The area of a triangle is equal to half times the base times the perpendicular height. Looking at triangle π΄π΅π in the diagram, we can take the base as 10 centimeters. And the perpendicular height here would be 11 centimeters. Looking at the calculation a half times 10 times 11, we can take a half of 10 as five. And then, five times 11 gives us 55. And the units here would be in squared centimeters since weβre dealing with an area. And so, our answer is that the area of triangle π΄π΅π is 55 square centimeters.