Finding the Fourth Proportional to 1,580.88, 2,181.47 and 917.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,580.88 : 2,181.47 = 917.76 : x
2. Step 2: Convert to fraction form
   1,580.88/2,181.47 = 917.76/x
3. Step 3: Cross multiply
   1,580.88x = 2,181.47 × 917.76
4. Step 4: Simplify right side
   1,580.88x = 2,002,069.50
5. Step 5: Solve for x
   x = 2,002,069.50/1,580.88
6. Step 6: Final answer
   x = 1,266.42