Finding the Fourth Proportional to 1,510.88, 2,085.53 and 999.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,510.88 : 2,085.53 = 999.88 : x
2. Step 2: Convert to fraction form
   1,510.88/2,085.53 = 999.88/x
3. Step 3: Cross multiply
   1,510.88x = 2,085.53 × 999.88
4. Step 4: Simplify right side
   1,510.88x = 2,085,269.52
5. Step 5: Solve for x
   x = 2,085,269.52/1,510.88
6. Step 6: Final answer
   x = 1,380.17