Answer:
Explanation
ayo so basically this is a pythagorus theorum question
the formula is
c²= a² + b²
where c is the hypotenuse (the longest line , opposite of the right angle aka here 13ft !!)
a and b , where a is the down line as a (4ft ) and b the unknown one
(just remember and lookout for the hypotenuse!)
so now put the numbers in formula
(13)²= (4)² +(b)²
169= 16 +(b)²
169-16=(b)²
153= (b)²
(put b first )
(b)² = 153
√(b)²= √153
(the square gets cut with the square root)
b= 12.36931688
b+12.4