Answer:
12
Step by step explaination:
Since PQRS is an isosceles trapezoid, two of its sides are equal. We can assume that QR and PS is the pair of congruent sides because of the ordering and naming of the whole trapezoid. That means that you just add 2 for the last side, PS, to the sum of all the other sides, giving you a total of 12. (2+3+5=10, 10+2=12)