Finding the Fourth Proportional to 1,429.20, 1,971.95 and 869.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,429.20 : 1,971.95 = 869.67 : x
2. Step 2: Convert to fraction form
   1,429.20/1,971.95 = 869.67/x
3. Step 3: Cross multiply
   1,429.20x = 1,971.95 × 869.67
4. Step 4: Simplify right side
   1,429.20x = 1,714,941.41
5. Step 5: Solve for x
   x = 1,714,941.41/1,429.20
6. Step 6: Final answer
   x = 1,199.93