The area of the parallelogram would be:
parallelogram area= length * width= 4*3=12
The area of the rectangle is count by multiplying the length and wide. In this picture, the length and wide is on diagonal line so you need to apply c^2= a^2+b^2 to find them.
length
length^2= a^2+b^2
length^2= 6^2+9^2
length^2= 117
length=√117
width
width^2= a^2+b^2
width^2= 2^2+3^2
width^2= 13
width= √13
rectangle area= length*width
rectangle area=√13*√117= √1521=39
Total area= 12+39= 51
