Problem: a triangle has sides 10 , 17 , and 21 . a square is inscribed in the triangle . one side of the square lies on the longest side of the triangle . the other two vertices of the square touch the two shorter sides of the triangle . what is the length of the side of the square ? 
Options: ['a ) 148 / 29', 'b ) 168 / 29', 'c ) 168 / 26', 'd ) 158 / 29', 'e ) 198 / 29']
b