The distance between two points (x₁,y1),(x₂,y₂) is d

For the given problem we have
W(1,8),X(7,8),Y(4,5), and Z(1,2)
The length of WY =
= 3√2
The length of WX =
= 6
The length of WZ =
= 6
The length of XY =
= 3√2
The length of ZY =
= 3√2
∴ WX = WZ ⇒⇒⇒ proved
XY = ZY ⇒⇒⇒ proved
WY = WY ⇒⇒⇒ reflexive property
∴ ΔWYZ is congruent to ΔWYX by SSS method