Can someone help me? It's urgent and thank you!

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

Joe has some money in his bank account he deposits 45$ write an expression that represents the amount of money in joe's account