Finding the Fourth Proportional to 1,061.99, 1,465.66 and 642.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.99 : 1,465.66 = 642.57 : x
2. Step 2: Convert to fraction form
   1,061.99/1,465.66 = 642.57/x
3. Step 3: Cross multiply
   1,061.99x = 1,465.66 × 642.57
4. Step 4: Simplify right side
   1,061.99x = 941,796.47
5. Step 5: Solve for x
   x = 941,796.47/1,061.99
6. Step 6: Final answer
   x = 886.82