17+15+b = 180 so If you do 180-(15+17) =b
Well we know 15+17 is 32 so now you do 180-32 which equals 148 so b=148
I worked backwards to solve this question, my explanation and working out is
in the picture. If you need any clarification, just ask in the comments.
If it didn't have that piece cut out on the bottom, it would be a rectangle that's 9cm wide and 5cm high. Its area would be 9x5= 45 cm².
But that piece is cut out of the bottom. The cut-out piece is 3cm wide and 3cm high, so its area is 3x3= 9 cm².
9 cm² have been cut out of the 45 cm² of the complete big rectangle. So the remaining area of the figure is 45 - 9 =<em> 36 cm²</em> .
4 would be the whole number. 0.8 would be 4/5 so the mixed number is 4 and 4/5.