Answer:
The dimensions of the enlarged poster are
by

Explanation:
we know that
The scale factor is equal to the measure of the corresponding side of the enlarged poster divide by the the measure of the corresponding side of the original poster
Let
z-----> scale factor
x------> the measure of the corresponding side of the enlarged poster
y------> the measure of the corresponding side of the original poster
so

In this problem we have

Step 1
Find the length of the enlarged poster

we have


substitute

Step 2
Find the width of the enlarged poster

we have


substitute

therefore
the dimensions of the enlarged poster are
by
