Finding the Fourth Proportional to 21,123.26, 31,671.52 and 17,990.99

Step by Step Solution

1. Step 1: Write the proportion equation
   21,123.26 : 31,671.52 = 17,990.99 : x
2. Step 2: Convert to fraction form
   21,123.26/31,671.52 = 17,990.99/x
3. Step 3: Cross multiply
   21,123.26x = 31,671.52 × 17,990.99
4. Step 4: Simplify right side
   21,123.26x = 569,801,796.27
5. Step 5: Solve for x
   x = 569,801,796.27/21,123.26
6. Step 6: Final answer
   x = 26,975.09