An arc of a circle has the same measure as the central angle that intercepts it.
Central angle 1 intercepts arc AB.
The measure of central angle 1 is the same as the measure of angle AB.
The measure of arc AB is 30 deg.
The are of his backyard is 10.4 times 15.83 or 164.632 yd^2
the sod piecs are 1.33 by 1.33 or 1.78 yd^2
so divide 164.632 by 1.78 or
164.632/1.78=92.5 pieces of sod
if he is buying the sod in pieces, he will have to buy 93 pieces because he can't buy 1/2 sod

If
, then we can immediately cancel the factors of
:

Factorize the numerator and denominator:


Next, if
, then

So, first, what are the two sides?
let's call then x and y
we know that 2(x+y)=12.5 (that's the distance around)
so that means that x+y=6.25 (I just divided both by 2)
now, x=4y (from "4 times as long as it is wide")
so we can substitute:
x+4x=6.25
5x=6.25
x=1.25
so one side, is 1.25 and the other will be 1.25*4=5
and for the area we multiply the two:
1.25*5=6.25 square kilometers, and this is the answer!