Answer:
17
Step-by-step explanation:
let x be the number of boxes to be shaded to make it 80%
x = 80% of total number
= 80/100 of 25
= 80/4
= 20
So 20 need to be shaded to fill 80%
Now, 13 of the grids are already shared so the amount of more squares that need to be shaded = 20-13
= 17 squares
Use angle sum property (the 3 angles in a triangle sum up to 180°).
2x + x + 54 = 180
3x + 54 = 180
3x = 180 - 54
3x = 126
x = 126/3
x = 42
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Hope it helps ⚜
