Question 701394
To find missing side lengths in right triangles we use Pythagoras' Theorem which is
{{{a^2+b^2=c^2}}} 
where a and b are the lengths of the short sides of the triangle and c is the length of the longest side of the triangle, (this is called the hypotenuse)
So a=8 and b=15. Putting those numbers into the equation gives
{{{8^2+15^2=c^2}}} 
working out the numbers gives
{{{64+225=c^2}}} i.e. {{{c^2=289}}}
because we need to find what c is, we need to take the square root of 289
{{{c=sqrt(289)}}}
Therefore c = 17.
the pipe needs to be 17 ft long.