Finding the Fourth Proportional to 1,915.48, 2,875.88 and 991.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.48 : 2,875.88 = 991.72 : x
2. Step 2: Convert to fraction form
   1,915.48/2,875.88 = 991.72/x
3. Step 3: Cross multiply
   1,915.48x = 2,875.88 × 991.72
4. Step 4: Simplify right side
   1,915.48x = 2,852,067.71
5. Step 5: Solve for x
   x = 2,852,067.71/1,915.48
6. Step 6: Final answer
   x = 1,488.96