Finding the Fourth Proportional to 1,061.91, 1,465.12 and 642.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.91 : 1,465.12 = 642.50 : x
2. Step 2: Convert to fraction form
   1,061.91/1,465.12 = 642.50/x
3. Step 3: Cross multiply
   1,061.91x = 1,465.12 × 642.50
4. Step 4: Simplify right side
   1,061.91x = 941,338.57
5. Step 5: Solve for x
   x = 941,338.57/1,061.91
6. Step 6: Final answer
   x = 886.46