Finding the Fourth Proportional to 100.83, 139.13 and 56.56

Step by Step Solution

1. Step 1: Write the proportion equation
   100.83 : 139.13 = 56.56 : x
2. Step 2: Convert to fraction form
   100.83/139.13 = 56.56/x
3. Step 3: Cross multiply
   100.83x = 139.13 × 56.56
4. Step 4: Simplify right side
   100.83x = 7,869.54
5. Step 5: Solve for x
   x = 7,869.54/100.83
6. Step 6: Final answer
   x = 78.05