Answer: 25 units
Step-by-step explanation: The difference between x-values is 23-3 = 20
The difference between y-values is -18 -(-3)= 15
Use the Pythagorean Theorem to find the length of the hypotenuse that completes the imaginary triangle. This is a classic 3-4-5 Pythagorean Triple. The calculated sides are in the ratio of 15:20, multiples of 5. So the remaining side is 5 times 5: 25