Congruency means that two figures or items are exactly the same size and shape. Where in life would it be vitally important for two or more items to be congruent?
My first thought would be wheels on a car... does anyone else have any better ideas?
Thanks!!! :)
Bridge parts
Thrust in multi engine rockets
Airplane wings, landing gear...
The outriggers (Hydraulic jacks on arms) on mobile cranes..
The footings of buildings
While it feels really weird, you can drive a 2 wheel drive car on different sized wheels. Different sized wheels on a 4 wheel drive car will break the drive system.
Different sized wheels on a skateboard would make it imposable to ride.