Finding the Fourth Proportional to 1,380.72, 2,071.32 and 456.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.72 : 2,071.32 = 456.60 : x
2. Step 2: Convert to fraction form
   1,380.72/2,071.32 = 456.60/x
3. Step 3: Cross multiply
   1,380.72x = 2,071.32 × 456.60
4. Step 4: Simplify right side
   1,380.72x = 945,764.71
5. Step 5: Solve for x
   x = 945,764.71/1,380.72
6. Step 6: Final answer
   x = 684.98