Finding the Fourth Proportional to 1,438.71, 2,156.69 and 917.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,438.71 : 2,156.69 = 917.24 : x
2. Step 2: Convert to fraction form
   1,438.71/2,156.69 = 917.24/x
3. Step 3: Cross multiply
   1,438.71x = 2,156.69 × 917.24
4. Step 4: Simplify right side
   1,438.71x = 1,978,210.02
5. Step 5: Solve for x
   x = 1,978,210.02/1,438.71
6. Step 6: Final answer
   x = 1,374.99