`A B C D` is a parallelogram and `A P Q` is a straight line meeting `B C` at `Pa n dD C` produced at `Qdot` prove that the rectangle obtained by `B Pa n dD Q` is equal to the rectangle contained by `A Ba n dB Cdot`

Explanation

To prove that the rectangle obtained by \( BP \) and \( DQ \) is equal to the rectangle contained by \( AB \) and \( BC \), we will follow these steps:

### Step 1: Understand the Given Information
We have a parallelogram \( ABCD \) and a straight line \( APQ \) that intersects \( BC \) at point \( P \) and extends to point \( Q \) beyond \( D \).