Answer:
160 is a whole angle so 37+72=109 160-109=51
51 is your answer
Step-by-step explanation:
To model half-life, use the formula

. Here,

is the amount remaining after a length of time

.

is the amount that you start with.

is the half-life. You plug in 50 for

, 10 for

, and 25 for

. You get

.
Since, each side of the fence should have the 1 3/4 feet wide decorative piece, the width of the fence should be subtracted by 2 pieces (1 3/4 feet)
= 26.5 feet
Then, divide the remaining width by 4.5 feet and the answer is 5.88. Thus, approximately 5 pieces of the 4 1/2 feet should be installed.