C) 225m
Step-by-step explanation:
Looking at the board we see each side is 25m in length. Each side has 5 squares, therefore the length of one side of each square is 5m (25m/5=5).
Let’s count how many full squares there are. There’s 5 completely full squares (one in the middle, and one on each of the four edges).
There’s also half-full squares which we COULD calculate separately using the area of a triangle. However, we know that two halves make one full square so let’s count how many full blocks these make up. There’s 8 triangles (or half full squares), therefore there are 4 full squares.
Adding this to the clearly full blocks shows 4+5=9. There are 9 fully shaded squares. The area of a square is A=s x s (Area = length of side x length of side). Therefore, one square’s area is 5x5=25m^2. The area of 9 squares is 25 x 9 = 225m^2.
Therefore the answer is C