Question

sort the words according to the meanings of their shared roots. fraction fractious quadratic refract quadruped diffraction break four

Explanation:

The root "fract-" means break. "Fraction" (a broken - off part), "fractious" (easily broken into parts or irritable as if easily 'broken' in mood), "refract" (bend or break light as it passes through a medium), and "diffraction" (the bending or breaking of waves around an obstacle) all relate to break. The root "quadr -" or "quad -" means four. "Quadratic" (involving the second power, related to a square which has four sides), "quadruped" (an animal with four feet) are related to four.

Answer:

break: fraction, fractious, refract, diffraction
four: quadratic, quadruped