Finding the Fourth Proportional to 31,785.72, 47,680.92 and 8,412

Step by Step Solution

1. Step 1: Write the proportion equation
   31,785.72 : 47,680.92 = 8,412 : x
2. Step 2: Convert to fraction form
   31,785.72/47,680.92 = 8,412/x
3. Step 3: Cross multiply
   31,785.72x = 47,680.92 × 8,412
4. Step 4: Simplify right side
   31,785.72x = 401,091,899.04
5. Step 5: Solve for x
   x = 401,091,899.04/31,785.72
6. Step 6: Final answer
   x = 12,618.62