Finding the Fourth Proportional to 1,686.89, 2,328.15 and 988.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,686.89 : 2,328.15 = 988.28 : x
2. Step 2: Convert to fraction form
   1,686.89/2,328.15 = 988.28/x
3. Step 3: Cross multiply
   1,686.89x = 2,328.15 × 988.28
4. Step 4: Simplify right side
   1,686.89x = 2,300,864.08
5. Step 5: Solve for x
   x = 2,300,864.08/1,686.89
6. Step 6: Final answer
   x = 1,363.97