Find the area of trapezium ABCD as given in the figure in which ADCE is a rectangle. (Hint: ABCD has two parts)
area of trapezium ABCD = area of rectangle ADCE + area(ΔBEC)…(i)
let us find area of rectangle ADCE
length = AD = 8 cm
breadth = AE = 3 cm
area of rectangle = length × breadth
⇒ area of rectangle ADCE = length × breadth
= AD × AE
= 8 × 3
= 24 sq. cm
Therefore, area of rectangle ADCE = 24 sq. cm
From figure EC || AD
⇒ ∠BEC = ∠EAD = 90° …corresponding angles
⇒ ∠BEC = 90°
And since ADCE is a rectangle EC = AD
⇒ EC = 8 cm
Now let us find area(ΔBEC)
area of triangle = 
× base × height
⇒ area(ΔBEC) = 
× EC × BE
⇒ area(ΔBEC) = 
× 8 × 3
⇒ area(ΔBEC) = 4 × 3
⇒ area(ΔBEC) = 12 cm2
From (i)
area of trapezium ABCD = area of rectangle ADCE + area(ΔBEC)…(i)
= 24 + 12
= 36 sq. cm
therefore, area of trapezium ABCD = 36 sq. cm