Answer:
See explanation
Step-by-step explanation:
A parallelogram is a quadrilateral with parallel opposite sides. The main property of a parallelogram is that the opposite sides of the parallelogram are congruent.
1. Sides AB and CD are congruent, then
[tex]4x=18\\ \\x=\dfrac{18}{4}=4.5[/tex]
2. Sides AD and BC are congruent, so
[tex]\dfrac{1}{3}x=7\\ \\x=7\cdot 3=21[/tex]
3. Sides AD and BC are congruent, so
[tex]x+4=15\\ \\x+4-4=15-4\\ \\x=11[/tex]