Add all the angles

Find the sum of all of the angles denoted by letters in this diagram
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative


Each letter in this diagram represents the angle between the two lines framing it.

What is the sum of all of the angles denoted by letters?

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Add all the angles


This problem is adapted from the World Mathematics Championships