Copyright © University of Cambridge. All rights reserved.
'Parallelogram in the Middle' printed from http://nrich.maths.org/
The diagram, which is not drawn accurately, shows a parallelogram inside a triangle.The marked lengths are equal.
What is the value of $x$?
If you liked this problem, here is an NRICH task
which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.