Finding the Fourth Proportional to 69.78, 104.64 and 56.10

Step by Step Solution

1. Step 1: Write the proportion equation
   69.78 : 104.64 = 56.10 : x
2. Step 2: Convert to fraction form
   69.78/104.64 = 56.10/x
3. Step 3: Cross multiply
   69.78x = 104.64 × 56.10
4. Step 4: Simplify right side
   69.78x = 5,870.30
5. Step 5: Solve for x
   x = 5,870.30/69.78
6. Step 6: Final answer
   x = 84.13