Finding the Fourth Proportional to 3,947.15, 5,430.30 and 3,837.80

Step by Step Solution

1. Step 1: Write the proportion equation
   3,947.15 : 5,430.30 = 3,837.80 : x
2. Step 2: Convert to fraction form
   3,947.15/5,430.30 = 3,837.80/x
3. Step 3: Cross multiply
   3,947.15x = 5,430.30 × 3,837.80
4. Step 4: Simplify right side
   3,947.15x = 20,840,405.34
5. Step 5: Solve for x
   x = 20,840,405.34/3,947.15
6. Step 6: Final answer
   x = 5,279.86