Finding the Fourth Proportional to 1,061.80, 1,465.37 and 642.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.80 : 1,465.37 = 642.17 : x
2. Step 2: Convert to fraction form
   1,061.80/1,465.37 = 642.17/x
3. Step 3: Cross multiply
   1,061.80x = 1,465.37 × 642.17
4. Step 4: Simplify right side
   1,061.80x = 941,017.11
5. Step 5: Solve for x
   x = 941,017.11/1,061.80
6. Step 6: Final answer
   x = 886.25