Finding the Fourth Proportional to 21,402, 29,520.69 and 12,898.35

Step by Step Solution

1. Step 1: Write the proportion equation
   21,402 : 29,520.69 = 12,898.35 : x
2. Step 2: Convert to fraction form
   21,402/29,520.69 = 12,898.35/x
3. Step 3: Cross multiply
   21,402x = 29,520.69 × 12,898.35
4. Step 4: Simplify right side
   21,402x = 380,768,191.86
5. Step 5: Solve for x
   x = 380,768,191.86/21,402
6. Step 6: Final answer
   x = 17,791.24