Finding the Fourth Proportional to 72,658.72, 100,317.96 and 64,978.16

Step by Step Solution

1. Step 1: Write the proportion equation
   72,658.72 : 100,317.96 = 64,978.16 : x
2. Step 2: Convert to fraction form
   72,658.72/100,317.96 = 64,978.16/x
3. Step 3: Cross multiply
   72,658.72x = 100,317.96 × 64,978.16
4. Step 4: Simplify right side
   72,658.72x = 6,518,476,455.75
5. Step 5: Solve for x
   x = 6,518,476,455.75/72,658.72
6. Step 6: Final answer
   x = 89,713.62