This is the Commutative Property of addition. called Commutative because the numbers move around to the other order, or "commute"
If they have 11 boxes and 88 shorts there will be 8 shorts in each box
For a better understanding of the solution given here please find the attached file which has the relevant diagram.
To answer this question we will have to make use of <u>the Isosceles Triangle Theorem</u> which states that the perpendicular bisector of the base of an isosceles triangle is also the angle bisector of the vertex angle. Thus, as a corollary we know that is EF is the angle bisector of the vertex angle ∠E, then, EF is the perpendicular bisector of the of the base DK.
Please follow the diagram of a complete understanding of the logic and the solution.
As EF is the angle bisector as given in the question, thus we will have:
.
Also, from the Theorem we know that KF will be half of DK and thus, KF will be:
centimeters.
Likewise, from the same theorem we have: 
First, determine the circumference (C) of the circle, the equation,
C = 2πr
Substituting the value or the radius,
C = 2π ( 4) = 8π
The arc length is the product of the circumference and the ratio between the subtended angle and 360. The mathematical expression is already,
S = (8π) x (72 / 360) = 0.8π
Thus, the arc is 0.80π.