Finding the Fourth Proportional to 12,915.30, 17,818.86 and 7,877.70

Step by Step Solution

1. Step 1: Write the proportion equation
   12,915.30 : 17,818.86 = 7,877.70 : x
2. Step 2: Convert to fraction form
   12,915.30/17,818.86 = 7,877.70/x
3. Step 3: Cross multiply
   12,915.30x = 17,818.86 × 7,877.70
4. Step 4: Simplify right side
   12,915.30x = 140,371,633.42
5. Step 5: Solve for x
   x = 140,371,633.42/12,915.30
6. Step 6: Final answer
   x = 10,868.63