Finding the Fourth Proportional to 1,345.77, 2,017.78 and 642.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.77 : 2,017.78 = 642.69 : x
2. Step 2: Convert to fraction form
   1,345.77/2,017.78 = 642.69/x
3. Step 3: Cross multiply
   1,345.77x = 2,017.78 × 642.69
4. Step 4: Simplify right side
   1,345.77x = 1,296,807.03
5. Step 5: Solve for x
   x = 1,296,807.03/1,345.77
6. Step 6: Final answer
   x = 963.62