Tetromino diagonal

Can you calculate the length of this diagonal line?
Age
14 to 16
Challenge level
filled star empty star empty star
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem



Four unit squares are placed edge to edge as shown. What is the length of the diagonal line drawn?

Tetromino Diagonal


If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.