Finding the Fourth Proportional to 12,915.78, 17,820.87 and 7,611.09

Step by Step Solution

1. Step 1: Write the proportion equation
   12,915.78 : 17,820.87 = 7,611.09 : x
2. Step 2: Convert to fraction form
   12,915.78/17,820.87 = 7,611.09/x
3. Step 3: Cross multiply
   12,915.78x = 17,820.87 × 7,611.09
4. Step 4: Simplify right side
   12,915.78x = 135,636,245.45
5. Step 5: Solve for x
   x = 135,636,245.45/12,915.78
6. Step 6: Final answer
   x = 10,501.59