Finding the Fourth Proportional to 20,865.72, 31,279.10 and 7,005

Step by Step Solution

1. Step 1: Write the proportion equation
   20,865.72 : 31,279.10 = 7,005 : x
2. Step 2: Convert to fraction form
   20,865.72/31,279.10 = 7,005/x
3. Step 3: Cross multiply
   20,865.72x = 31,279.10 × 7,005
4. Step 4: Simplify right side
   20,865.72x = 219,110,095.50
5. Step 5: Solve for x
   x = 219,110,095.50/20,865.72
6. Step 6: Final answer
   x = 10,500.96