Finding the Fourth Proportional to 28,040.79, 42,061.28 and 8,319.50

Step by Step Solution

1. Step 1: Write the proportion equation
   28,040.79 : 42,061.28 = 8,319.50 : x
2. Step 2: Convert to fraction form
   28,040.79/42,061.28 = 8,319.50/x
3. Step 3: Cross multiply
   28,040.79x = 42,061.28 × 8,319.50
4. Step 4: Simplify right side
   28,040.79x = 349,928,567.06
5. Step 5: Solve for x
   x = 349,928,567.06/28,040.79
6. Step 6: Final answer
   x = 12,479.27