$$\sqrt{41^{2} - 9^{2}} + \sqrt{8^{2} + 15^{2}}=$$． 
Overseas Competition->Knowledge Point->Number Theory Modules->Perfect Square Numbers->Basic Applications of Square Numbers
$$\sqrt{41^{2} - 9^{2}} + \sqrt{8^{2} + 15^{2}}=\sqrt{1600} + \sqrt{289} = 40 + 17 = 57$$. 