Finding the Fourth Proportional to 21,978.48, 32,972.94 and 7,187.40

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.48 : 32,972.94 = 7,187.40 : x
2. Step 2: Convert to fraction form
   21,978.48/32,972.94 = 7,187.40/x
3. Step 3: Cross multiply
   21,978.48x = 32,972.94 × 7,187.40
4. Step 4: Simplify right side
   21,978.48x = 236,989,708.96
5. Step 5: Solve for x
   x = 236,989,708.96/21,978.48
6. Step 6: Final answer
   x = 10,782.81