Finding the Fourth Proportional to 1,462.09, 2,191.28 and 640.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,462.09 : 2,191.28 = 640.15 : x
2. Step 2: Convert to fraction form
   1,462.09/2,191.28 = 640.15/x
3. Step 3: Cross multiply
   1,462.09x = 2,191.28 × 640.15
4. Step 4: Simplify right side
   1,462.09x = 1,402,747.89
5. Step 5: Solve for x
   x = 1,402,747.89/1,462.09
6. Step 6: Final answer
   x = 959.41