Multiply 15 with 12
15 x 12 = 180 (total area, including the hole).
Find the area of the hole. Subtract 2 fives from 12.
2(5) = 10
12 - 10 = 2
The side measurement is 8
8 x 2 = 16m²
Subtract 16 from 180
180 - 16 = 164m²
164 m² should be your answer
hope this helps