How do you get the length of a rectangle corner to corner?

Hmm. Just place a ruler so one edge is at one corner and then swing the ruler around to the opposite corner and read the distance.Is that what you meant?Answer 2 Why don't you just put a ruler from...

measure one side of the square then multiply by 1.414 ex. a 10 in. square will have a corner to corner length of 14.14 in.

Diagonal of a rectangle or square = square root of ( length2 + width2 )

Five

1. ok you have four coordinates A (0,0) B (0,1) C (1,0) D (1,1) 2. chart your coordinates on a grid (these should make a square when you connect them in order) 3. count the units between the points