Finding the Fourth Proportional to 1,492.78, 2,238.88 and 438.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,492.78 : 2,238.88 = 438.72 : x
2. Step 2: Convert to fraction form
   1,492.78/2,238.88 = 438.72/x
3. Step 3: Cross multiply
   1,492.78x = 2,238.88 × 438.72
4. Step 4: Simplify right side
   1,492.78x = 982,241.43
5. Step 5: Solve for x
   x = 982,241.43/1,492.78
6. Step 6: Final answer
   x = 657.99