we know that
<u>Part 1) </u>
we know that
side 1=15'-7"
side 2=20'-4"
side 3=26'-2"
To find the total length of three sides sum the three sides
so
total length=side 1+side 2 +side 3
substitute
total length=15'-7"+20'-4"+26'-2"
total length=(15'+20'+26')+(7"+4"+2")
total length=(61')+(13")
remember that
12"=1'
13"=12"+1"=1'+1"
substitute
total length=(61')+(1'+1")
total length=(62')+(1")---------> 62'-1"
therefore
<u>the answer is</u>
the total length of three sides is 62'-1"