Finding the Fourth Proportional to 1,408.42, 2,111.28 and 921.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.42 : 2,111.28 = 921.88 : x
2. Step 2: Convert to fraction form
   1,408.42/2,111.28 = 921.88/x
3. Step 3: Cross multiply
   1,408.42x = 2,111.28 × 921.88
4. Step 4: Simplify right side
   1,408.42x = 1,946,346.81
5. Step 5: Solve for x
   x = 1,946,346.81/1,408.42
6. Step 6: Final answer
   x = 1,381.94