There is a slide in a park. One of its side walls has been painted in some colour with a message “KEEP THE PARK GREEN AND CLEAN”. If the sides of the wall are 15 m, 11 m and 6 m, find the area painted in colour.

Explanation

To find the area of the painted wall in the park, we will use Heron's formula. The sides of the wall are given as 15 m, 11 m, and 6 m. Let's solve this step by step.

### Step 1: Identify the sides of the triangle
Let the sides of the triangle be:
- \( a = 15 \, \text{m} \)
- \( b = 11 \, \text{m} \)
- \( c = 6 \, \text{m} \)

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