Finding the Fourth Proportional to 1,688.84, 2,330.82 and 990.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,688.84 : 2,330.82 = 990.28 : x
2. Step 2: Convert to fraction form
   1,688.84/2,330.82 = 990.28/x
3. Step 3: Cross multiply
   1,688.84x = 2,330.82 × 990.28
4. Step 4: Simplify right side
   1,688.84x = 2,308,164.43
5. Step 5: Solve for x
   x = 2,308,164.43/1,688.84
6. Step 6: Final answer
   x = 1,366.72