P = AB + BC +CD + DE + EA
If the polygon is dilated using a scale facor of 3, then:
3P = 3AB + 3BC + 3CD + 3DE +3EA
Factor:
3P = 3(AB + BC +CD + DE + EA)
Therefore, The perimeter is 3 times bigger.
Since the area depends on the sides and the sides have been expanded by a factor of 3:
A = k² square units
So:
A = 3³ square units
A = 9 square units
Therefore the area is 9 times bigger