It is given in the question that,

ABCD is a quadrilateral, where

AC = 22 cm

BM = 3 cm

DN = 3 cm

BM is perpendicular to AC and DN is perpendicular to AC

∴ Area of (ABCD) = Area (ABC) + Area (ADC)

= × (3 × 22) + × (3 × 22)

= × 66 + × 66

= 33 + 33

= 66 cm