Answer:
1)
-------->

2)
-------->

3)
-------->

4)
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Explanation:
Verify each case
case 1)

Find the area with the original dimensions

Reduce the area of the poster by one-third

therefore
-------->

case 2)

Find the area with the original dimensions

Reduce the area of the poster by one-third

therefore
-------->

case 3)

Find the area with the original dimensions

Reduce the area of the poster by one-third

therefore
-------->

case 4)

Find the area with the original dimensions

Reduce the area of the poster by one-third

therefore
-------->
