Finding the Fourth Proportional to 1,312.86, 1,967.72 and 581.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,312.86 : 1,967.72 = 581.61 : x
2. Step 2: Convert to fraction form
   1,312.86/1,967.72 = 581.61/x
3. Step 3: Cross multiply
   1,312.86x = 1,967.72 × 581.61
4. Step 4: Simplify right side
   1,312.86x = 1,144,442.72
5. Step 5: Solve for x
   x = 1,144,442.72/1,312.86
6. Step 6: Final answer
   x = 871.72