Finding the Fourth Proportional to 1,421.42, 1,961.72 and 862.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.42 : 1,961.72 = 862.07 : x
2. Step 2: Convert to fraction form
   1,421.42/1,961.72 = 862.07/x
3. Step 3: Cross multiply
   1,421.42x = 1,961.72 × 862.07
4. Step 4: Simplify right side
   1,421.42x = 1,691,139.96
5. Step 5: Solve for x
   x = 1,691,139.96/1,421.42
6. Step 6: Final answer
   x = 1,189.75