Finding the Fourth Proportional to 28,606.50, 42,912.72 and 7,830

Step by Step Solution

1. Step 1: Write the proportion equation
   28,606.50 : 42,912.72 = 7,830 : x
2. Step 2: Convert to fraction form
   28,606.50/42,912.72 = 7,830/x
3. Step 3: Cross multiply
   28,606.50x = 42,912.72 × 7,830
4. Step 4: Simplify right side
   28,606.50x = 336,006,597.60
5. Step 5: Solve for x
   x = 336,006,597.60/28,606.50
6. Step 6: Final answer
   x = 11,745.81