 Hello and welcome to the session. In this session we discussed the following question which says, ABCT is a parallelogram of area 900 cm2. AP is a perpendicular drawn to BC and AQ is a perpendicular drawn to DC if AP is equal to 20 cm and AQ is equal to 30 cm, calculate AB and BC. Before moving on to the solution let's recall one theorem which says that the area of a parallelogram is the product of any of its sides and the corresponding altitude. This is the key idea that we use in this question. Let's proceed with the solution now. We are given that this ABCD is a parallelogram and we have area of the parallelogram ABCD is equal to 900 cm2. We are also given that AP is a perpendicular drawn to the side BC so AP is perpendicular to BC and AQ is a perpendicular drawn to the side BC so AQ is perpendicular to DC. We have AP is equal to 20 cm and AQ is equal to 30 cm. We are supposed to calculate AB and BC. We have that the area of the parallelogram ABCD is equal to 900 cm2 and from the key idea we have that the area of a parallelogram is the product of any of its sides and the corresponding altitude. So from the figure we have that the area of the parallelogram ABCD is equal to the product of its side AB and the corresponding altitude that is AQ. So this means that 900 cm2 is equal to AB multiplied by AQ which is of measure 30 cm. So this means that AB is equal to 900 upon 30 cm. This means that we get AB is equal to 30 cm. So we have calculated the length of AB. Now further area of the parallelogram ABCD is equal to the product of its side BC and the corresponding altitude that is AP. Now this means that 900 cm2 is equal to BC multiplied by AP which is of measure 20 cm. This gives us BC is equal to 900 cm2 upon 20 cm. Therefore we get BC equal to 45 cm. Thus our final answer is AB equal to 30 cm and BC equal to 45 cm. This completes the session. Hope you have understood the solution of this question.