To find the area of `triangleABC`, note that the lengths of the sides of `triangleABC` form (3-4-5) Pythagorean triple, where `AC=4`. Hence, Find the area of `triangleABC`.

Answer

To find the area of triangle ABC, we can follow these steps:

### Step 1: Identify the sides of the triangle
Given that triangle ABC forms a Pythagorean triplet (3-4-5) and that AC = 4, we can identify the sides of the triangle:
- AC = 4 (one of the perpendicular sides)
- BC = 3 (the other perpendicular side)
- AB = 5 (the hypotenuse)

### Step 2: Understand the triangle configuration
Since AC and BC are the two perpendicular sides, we can visualize triangle ABC as a right-angled triangle with:
- AC as the height
- BC as the base

### Step 3: Use the area formula for a triangle
The area \( A \) of a triangle can be calculated using the formula:
\[ A = \frac{1}{2} \times \text{base} \times \text{height} \]
In our case:
- Base = BC = 3
- Height = AC = 4

### Step 4: Substitute the values into the formula
Now substituting the values into the area formula:
\[ A = \frac{1}{2} \times 3 \times 4 \]

### Step 5: Calculate the area
Calculating the above expression:
\[ A = \frac{1}{2} \times 12 = 6 \]

### Conclusion
Thus, the area of triangle ABC is \( 6 \) square units.

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