The sum of 3 consecutive even numbers is 78.

25, 26, 27

Step-by-step explanation:

set up an equation so 3 consecutive numbers are n, n+1, and n+2

So n + n +1 + n + 2 = 78, so 3n + 3 = 78, 3n = 75, so n = 25

so the numbers are 25, 26, 27

10 cm

step-by-step explanation:

if the polygon is a rectangle, then the perimeter is x+x+y+y. using the values that you gave, the perimeter is 3+3+2+2=10cm.