The polygons are similar Find the value of x

Answer:
The value of the x variable is 30.
Step-by-step explanation:
Since the triangles are similar, the corresponding sides of both triangles have a common ratio. The 18:12 ratio of side LK and QR is equal to 2:3, and the 21:14 ratio of sides JL and PQ is also equal to 2:3. Based on this, we know that 2/3 * x = 20, so we isolate the x variable by dividing both sides of the equation by 2/3 to get the answer: x = 30.