Answer:7
Step-by-step explanation:On a rectangle two sides will always be the same and the other two sides will be different but the same as each other. One side of a rectangle is 12 & there is another side of 12( perimeter is all sides added together ), so add 12+12=24 and then subtract 38-24=14( 14 is the two sides left added together , so 14•/•2 =7. 7+7=14, 12+12=24 ; 14+24=38. You can also add each number individually to check.
