Finding the Fourth Proportional to 915.86, 1,374.69 and 671.69

Step by Step Solution

1. Step 1: Write the proportion equation
   915.86 : 1,374.69 = 671.69 : x
2. Step 2: Convert to fraction form
   915.86/1,374.69 = 671.69/x
3. Step 3: Cross multiply
   915.86x = 1,374.69 × 671.69
4. Step 4: Simplify right side
   915.86x = 923,365.53
5. Step 5: Solve for x
   x = 923,365.53/915.86
6. Step 6: Final answer
   x = 1,008.20