Answer :

Area of square =6*6= 36 cm^2
Area of trapezoid =1/2( base1+base2)*height
base 1=7
base2=21-6=15
height=6
Area of trapezoid =1/2( 7+15)*6= 66 
whole area = area of square + area of trapezoid= 36+66=102
Answer 102