Finding the Fourth Proportional to 21,276.72, 31,884.84 and 15,686.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,276.72 : 31,884.84 = 15,686.10 : x
2. Step 2: Convert to fraction form
   21,276.72/31,884.84 = 15,686.10/x
3. Step 3: Cross multiply
   21,276.72x = 31,884.84 × 15,686.10
4. Step 4: Simplify right side
   21,276.72x = 500,148,788.72
5. Step 5: Solve for x
   x = 500,148,788.72/21,276.72
6. Step 6: Final answer
   x = 23,506.86