Finding the Fourth Proportional to 86,801.49, 129,989.91 and 78,387

Step by Step Solution

1. Step 1: Write the proportion equation
   86,801.49 : 129,989.91 = 78,387 : x
2. Step 2: Convert to fraction form
   86,801.49/129,989.91 = 78,387/x
3. Step 3: Cross multiply
   86,801.49x = 129,989.91 × 78,387
4. Step 4: Simplify right side
   86,801.49x = 10,189,519,075.17
5. Step 5: Solve for x
   x = 10,189,519,075.17/86,801.49
6. Step 6: Final answer
   x = 117,388.76