Finding the Fourth Proportional to 100,830.39, 139,145.91 and 56,128.95

Step by Step Solution

1. Step 1: Write the proportion equation
   100,830.39 : 139,145.91 = 56,128.95 : x
2. Step 2: Convert to fraction form
   100,830.39/139,145.91 = 56,128.95/x
3. Step 3: Cross multiply
   100,830.39x = 139,145.91 × 56,128.95
4. Step 4: Simplify right side
   100,830.39x = 7,810,113,825.09
5. Step 5: Solve for x
   x = 7,810,113,825.09/100,830.39
6. Step 6: Final answer
   x = 77,457.94