$322.56
You change 28% to .28 then multiply that with $448=$125.44
Then you minus that from $448=$322.56
B: (0, a)
C should have the same y value as B
D: (a,0)
C should have the same x value as D
So point C is (a,a)
Since point A is on the origin, its point is (0,0)
You use the slope formula and plug in point A and C:



m = 1
So the value that belongs in the green box is 1
Yes the answer is option A
3.9 is the estimated square root of 15 to one decimal place