Finding the Fourth Proportional to 78.85, 108.70 and 49.69

Step by Step Solution

1. Step 1: Write the proportion equation
   78.85 : 108.70 = 49.69 : x
2. Step 2: Convert to fraction form
   78.85/108.70 = 49.69/x
3. Step 3: Cross multiply
   78.85x = 108.70 × 49.69
4. Step 4: Simplify right side
   78.85x = 5,400.91
5. Step 5: Solve for x
   x = 5,400.91/78.85
6. Step 6: Final answer
   x = 68.50