Finding the Fourth Proportional to 99,570.78, 137,315.37 and 72,670.68

Step by Step Solution

1. Step 1: Write the proportion equation
   99,570.78 : 137,315.37 = 72,670.68 : x
2. Step 2: Convert to fraction form
   99,570.78/137,315.37 = 72,670.68/x
3. Step 3: Cross multiply
   99,570.78x = 137,315.37 × 72,670.68
4. Step 4: Simplify right side
   99,570.78x = 9,978,801,312.35
5. Step 5: Solve for x
   x = 9,978,801,312.35/99,570.78
6. Step 6: Final answer
   x = 100,218.17