Question

Find the area of the PQRS

Answer 1

join SQ
then 
area of parallelogram SQDC = base x height
                                                 18x4=72
area of triangle SPQ= 1/2of 72 (= 36  triangle and parallelogram on same base the area of traingle 1/2 are of parallelogram)
similarly
Area SABQ = 1/2 OF RQS = 36
then area of PQRS = 72