Answer:
x = 4
Step-by-step explanation:
A trapezium is a quadrilateral (has four sides and four angles) with one pair of parallel sides. A trapezium is said to be isosceles if the bases are parallel, the two other sides known as the legs are equal and diagonals of the trapezium are equal to each other.
In trapezoid ABCD, BC and AD are the diagonals.
Hence BC = AD (property of isosceles trapezoid)
9x + 1 = 12x - 11
Simplifying:
12x - 9x = 1 + 11
3x = 12
Dividing both sides by 2:
x = 4
