Finding the Fourth Proportional to 1,638.84, 2,261.61 and 930.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,638.84 : 2,261.61 = 930.72 : x
2. Step 2: Convert to fraction form
   1,638.84/2,261.61 = 930.72/x
3. Step 3: Cross multiply
   1,638.84x = 2,261.61 × 930.72
4. Step 4: Simplify right side
   1,638.84x = 2,104,925.66
5. Step 5: Solve for x
   x = 2,104,925.66/1,638.84
6. Step 6: Final answer
   x = 1,284.40