Finding the Fourth Proportional to 123,976.17, 171,087.80 and 72,991.13

Step by Step Solution

1. Step 1: Write the proportion equation
   123,976.17 : 171,087.80 = 72,991.13 : x
2. Step 2: Convert to fraction form
   123,976.17/171,087.80 = 72,991.13/x
3. Step 3: Cross multiply
   123,976.17x = 171,087.80 × 72,991.13
4. Step 4: Simplify right side
   123,976.17x = 12,487,890,630.82
5. Step 5: Solve for x
   x = 12,487,890,630.82/123,976.17
6. Step 6: Final answer
   x = 100,728.15