Finding the Fourth Proportional to 100.82, 139.12 and 56.56

Step by Step Solution

1. Step 1: Write the proportion equation
   100.82 : 139.12 = 56.56 : x
2. Step 2: Convert to fraction form
   100.82/139.12 = 56.56/x
3. Step 3: Cross multiply
   100.82x = 139.12 × 56.56
4. Step 4: Simplify right side
   100.82x = 7,868.63
5. Step 5: Solve for x
   x = 7,868.63/100.82
6. Step 6: Final answer
   x = 78.05