Finding the Fourth Proportional to 1,308.78, 1,962.58 and 921.27

Step by Step Solution

1. Step 1: Write the proportion equation
   1,308.78 : 1,962.58 = 921.27 : x
2. Step 2: Convert to fraction form
   1,308.78/1,962.58 = 921.27/x
3. Step 3: Cross multiply
   1,308.78x = 1,962.58 × 921.27
4. Step 4: Simplify right side
   1,308.78x = 1,808,069.95
5. Step 5: Solve for x
   x = 1,808,069.95/1,308.78
6. Step 6: Final answer
   x = 1,381.49