Question 88043
Since we have a triangle with legs of 12 , 15 and a hypotenuse of x(our unknown side), we can use Pythagoreans theorem to find the unknown side.

Pythagoreans theorem
{{{a^2+b^2=c^2}}}


{{{12^2+15^2=c^2}}}  Plug in a=12 and b=15 and lets solve for c

{{{1 4 4 + 2 2 5 =  c  ^ 2}}} Square each individual term




{{{3 6 9 =  c  ^ 2}}} Combine like terms



{{{s q r t ( 3 6 9 ) = s q r t (  c  ^ 2 )}}} Take the square root of both sides



{{{3*sqrt(41)=c}}} Simplify the square root



Which approximates to...

{{{1 9 . 2 0 9 3 7 2 7 1 2 2 9 8 5 = c}}}


So our answer is

{{{c = 1 9 . 2 0 9 3 7 2 7 1 2 2 9 8 5}}}