Finding the Fourth Proportional to 1,380.35, 2,068.96 and 687.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.35 : 2,068.96 = 687.51 : x
2. Step 2: Convert to fraction form
   1,380.35/2,068.96 = 687.51/x
3. Step 3: Cross multiply
   1,380.35x = 2,068.96 × 687.51
4. Step 4: Simplify right side
   1,380.35x = 1,422,430.69
5. Step 5: Solve for x
   x = 1,422,430.69/1,380.35
6. Step 6: Final answer
   x = 1,030.49