First, let's write the formula:
A = 1/2 bh.
Next, substitute (2.4, 0.5, 3.5) for b and (3.5, 2.4, 0.5) for h. So we can use 2.4 for b and 3.5 for h:
A = 1/2 (2.4)(3.5).
Now, simplify by Multiplying:
A = 1/2 (8.4).
Now, simplify again by dividing:
A = 4.2 m².
The area of the sandbox is 4.2 m².