Finding the Fourth Proportional to 9,315.60, 12,855.53 and 5,123.85

Step by Step Solution

1. Step 1: Write the proportion equation
   9,315.60 : 12,855.53 = 5,123.85 : x
2. Step 2: Convert to fraction form
   9,315.60/12,855.53 = 5,123.85/x
3. Step 3: Cross multiply
   9,315.60x = 12,855.53 × 5,123.85
4. Step 4: Simplify right side
   9,315.60x = 65,869,807.39
5. Step 5: Solve for x
   x = 65,869,807.39/9,315.60
6. Step 6: Final answer
   x = 7,070.91