Finding the Fourth Proportional to 139,672.40, 209,562.36 and 64,830.80

Step by Step Solution

1. Step 1: Write the proportion equation
   139,672.40 : 209,562.36 = 64,830.80 : x
2. Step 2: Convert to fraction form
   139,672.40/209,562.36 = 64,830.80/x
3. Step 3: Cross multiply
   139,672.40x = 209,562.36 × 64,830.80
4. Step 4: Simplify right side
   139,672.40x = 13,586,095,448.69
5. Step 5: Solve for x
   x = 13,586,095,448.69/139,672.40
6. Step 6: Final answer
   x = 97,271.15