Finding the Fourth Proportional to 1,388.18, 1,915.68 and 758.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.18 : 1,915.68 = 758.72 : x
2. Step 2: Convert to fraction form
   1,388.18/1,915.68 = 758.72/x
3. Step 3: Cross multiply
   1,388.18x = 1,915.68 × 758.72
4. Step 4: Simplify right side
   1,388.18x = 1,453,455.15
5. Step 5: Solve for x
   x = 1,453,455.15/1,388.18
6. Step 6: Final answer
   x = 1,047.02