So we know the area A=595cm^2 of the square piece of fabric and we want to calculate one side to the nearest tenth. So the formula for the area of a square is A=a^2 so we simply need to take the square root of the area to get the lenght of one side: a=sqrt A=24.39262 cm. Rounded to the nearest tenth: a= 24.4 cm. So the correct answer is C. 24.4 cm