Finding the Fourth Proportional to 21,820.50, 30,112.35 and 12,390.54

Step by Step Solution

1. Step 1: Write the proportion equation
   21,820.50 : 30,112.35 = 12,390.54 : x
2. Step 2: Convert to fraction form
   21,820.50/30,112.35 = 12,390.54/x
3. Step 3: Cross multiply
   21,820.50x = 30,112.35 × 12,390.54
4. Step 4: Simplify right side
   21,820.50x = 373,108,277.17
5. Step 5: Solve for x
   x = 373,108,277.17/21,820.50
6. Step 6: Final answer
   x = 17,098.98