Finding the Fourth Proportional to 139,314.88, 209,007.68 and 64,489

Step by Step Solution

1. Step 1: Write the proportion equation
   139,314.88 : 209,007.68 = 64,489 : x
2. Step 2: Convert to fraction form
   139,314.88/209,007.68 = 64,489/x
3. Step 3: Cross multiply
   139,314.88x = 209,007.68 × 64,489
4. Step 4: Simplify right side
   139,314.88x = 13,478,696,275.52
5. Step 5: Solve for x
   x = 13,478,696,275.52/139,314.88
6. Step 6: Final answer
   x = 96,749.87