Apply geometrical facts, properties and relationships to find the sizes of unknown sides and angles of plane shapes in diagrams, providing appropriate reasons

1. Shape Up! 16 - calculate value of x, angle sum of quadrilateral, algebraic expression
2. Shape Up! 15 - calculate angle size, parallel line properties
3. Shape Up! 14 - calculate size of opposite angles, algebraic expression
4. Shape Up! 12 - calculate angle size, angle sum of a quadrilateral, algebraic expression