Answer:
x = 8
Step-by-step explanation:
remember:
When two triangles are congruent they will have exactly the same three sides and exactly the same three angles.
The equal sides and angles may not be in the same position (if there is a turn or a flip), but they are there.
based on the figure given:
AB=8 is also equal to BC=x=8
therefore, your x value would be 8
