Answer:
36 cm²
Explanation:
Area of a parallelogram = base x height
So area of parallelogram ABCD = BC x AM
To calculate the length of AM, use Pythagoras' Theorem a² + b² = c²
(where a and b are the legs and c is the hypotenuse of a right-angled triangle).
So using this theorem: BM² + AM² = AB²
⇒ 3² + AM² = 5²
⇒ AM² = 16
⇒ AM = √16 = 4 cm
(positive solution only as length cannot be negative)
Therefore, area of parallelogram ABCD = (3 + 6) x 4 = 9 x 4 = 36 cm²