Finding the Fourth Proportional to 16,890.21, 23,139.45 and 16,259.40

Step by Step Solution

1. Step 1: Write the proportion equation
   16,890.21 : 23,139.45 = 16,259.40 : x
2. Step 2: Convert to fraction form
   16,890.21/23,139.45 = 16,259.40/x
3. Step 3: Cross multiply
   16,890.21x = 23,139.45 × 16,259.40
4. Step 4: Simplify right side
   16,890.21x = 376,233,573.33
5. Step 5: Solve for x
   x = 376,233,573.33/16,890.21
6. Step 6: Final answer
   x = 22,275.25