Finding the Fourth Proportional to 257,420.72, 355,240.12 and 156,818.72

Step by Step Solution

1. Step 1: Write the proportion equation
   257,420.72 : 355,240.12 = 156,818.72 : x
2. Step 2: Convert to fraction form
   257,420.72/355,240.12 = 156,818.72/x
3. Step 3: Cross multiply
   257,420.72x = 355,240.12 × 156,818.72
4. Step 4: Simplify right side
   257,420.72x = 55,708,300,911.05
5. Step 5: Solve for x
   x = 55,708,300,911.05/257,420.72
6. Step 6: Final answer
   x = 216,409.55