Just like you drew those dotted lines. You know how to find the areas of rectangles which is A=length x width
The answer would be 20cm^2+6cm^2+18cm^2=44 cm^2
2x+1+4x-7=90°
6x-6=90°
6x=96
divide 96 by 6 and you get 16
x=16
4(16)-7
64-7=57°
The angle is 57°