Finding the Fourth Proportional to 100,428.56, 138,590.72 and 55,716.56

Step by Step Solution

1. Step 1: Write the proportion equation
   100,428.56 : 138,590.72 = 55,716.56 : x
2. Step 2: Convert to fraction form
   100,428.56/138,590.72 = 55,716.56/x
3. Step 3: Cross multiply
   100,428.56x = 138,590.72 × 55,716.56
4. Step 4: Simplify right side
   100,428.56x = 7,721,798,166.32
5. Step 5: Solve for x
   x = 7,721,798,166.32/100,428.56
6. Step 6: Final answer
   x = 76,888.47