Finding the Fourth Proportional to 1,320.72, 1,981.76 and 671.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.72 : 1,981.76 = 671.45 : x
2. Step 2: Convert to fraction form
   1,320.72/1,981.76 = 671.45/x
3. Step 3: Cross multiply
   1,320.72x = 1,981.76 × 671.45
4. Step 4: Simplify right side
   1,320.72x = 1,330,659.39
5. Step 5: Solve for x
   x = 1,330,659.39/1,320.72
6. Step 6: Final answer
   x = 1,007.53