First, balancing the chemical equation gives us 2HCl + Ca(OH)2 -> CaCl2 + 2H2O
Next, find the moles of reactant using the molar mass of calcium hydroxide.
(61.8 g Ca(OH)2) / (74.093 g/mol) = 0.8341 mol Ca(OH)2
Next, use the mole ratio given by the balanced chemical reaction to find moles of HCl
0.8341 mol Ca(OH)2 x 2 mol HCl / 1 mol Ca(OH)2 = 1.668 mol HCl
Finally, use the molar mass of HCl to find the grams of HCl needed.
1.668 mol HCl x 36.458 g/mol = 60.8 g HCl
Keep in mind, we use 3 significant figures because we were given 3 significant figures in the question.