Finding the Fourth Proportional to 1,378.32, 2,066.72 and 728.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.32 : 2,066.72 = 728.88 : x
2. Step 2: Convert to fraction form
   1,378.32/2,066.72 = 728.88/x
3. Step 3: Cross multiply
   1,378.32x = 2,066.72 × 728.88
4. Step 4: Simplify right side
   1,378.32x = 1,506,390.87
5. Step 5: Solve for x
   x = 1,506,390.87/1,378.32
6. Step 6: Final answer
   x = 1,092.92