Stellar angles

Weekly Problem 30 - 2013
What is the angle $x$ in the star shape shown?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

Problem

 
Image
Stellar Angles


What is the value of $x$ in the diagram?
          


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