Angle b = 90 degrees, side bc = 20, angle y = 90 degrees, and side yz = 20. what additional information would you need to prove that δabc≅δxyz by hl?

To prove that  δabc≅δxyz by hl, we need to have three pieces of information: 1- we need the two triangles  to be right-angled    (this one is given as angle b = angle y = 90 degrees)2- we need to have two corresponding congruent legs    (this one is given as bc = yz = 20)3- we need to have two congruent hypotenuses      (this means that we need to have ac = xz)the third piece of information is the missing one.

Idon’t understand this but 90