Finding the Fourth Proportional to 21,271.50, 31,921.83 and 7,420.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,271.50 : 31,921.83 = 7,420.50 : x
2. Step 2: Convert to fraction form
   21,271.50/31,921.83 = 7,420.50/x
3. Step 3: Cross multiply
   21,271.50x = 31,921.83 × 7,420.50
4. Step 4: Simplify right side
   21,271.50x = 236,875,939.52
5. Step 5: Solve for x
   x = 236,875,939.52/21,271.50
6. Step 6: Final answer
   x = 11,135.84