Finding the Fourth Proportional to 1,053.50, 1,578.86 and 915.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,053.50 : 1,578.86 = 915.89 : x
2. Step 2: Convert to fraction form
   1,053.50/1,578.86 = 915.89/x
3. Step 3: Cross multiply
   1,053.50x = 1,578.86 × 915.89
4. Step 4: Simplify right side
   1,053.50x = 1,446,053.05
5. Step 5: Solve for x
   x = 1,446,053.05/1,053.50
6. Step 6: Final answer
   x = 1,372.62