Finding the Fourth Proportional to 1,687.40, 2,280.45 and 1,687.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,687.40 : 2,280.45 = 1,687.40 : x
2. Step 2: Convert to fraction form
   1,687.40/2,280.45 = 1,687.40/x
3. Step 3: Cross multiply
   1,687.40x = 2,280.45 × 1,687.40
4. Step 4: Simplify right side
   1,687.40x = 3,848,031.33
5. Step 5: Solve for x
   x = 3,848,031.33/1,687.40
6. Step 6: Final answer
   x = 2,280.45