Finding the Fourth Proportional to 139,915.98, 209,711.35 and 79,986.45

Step by Step Solution

1. Step 1: Write the proportion equation
   139,915.98 : 209,711.35 = 79,986.45 : x
2. Step 2: Convert to fraction form
   139,915.98/209,711.35 = 79,986.45/x
3. Step 3: Cross multiply
   139,915.98x = 209,711.35 × 79,986.45
4. Step 4: Simplify right side
   139,915.98x = 16,774,066,411.21
5. Step 5: Solve for x
   x = 16,774,066,411.21/139,915.98
6. Step 6: Final answer
   x = 119,886.71