Finding the Fourth Proportional to 1,320.34, 1,980.60 and 670.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.34 : 1,980.60 = 670.72 : x
2. Step 2: Convert to fraction form
   1,320.34/1,980.60 = 670.72/x
3. Step 3: Cross multiply
   1,320.34x = 1,980.60 × 670.72
4. Step 4: Simplify right side
   1,320.34x = 1,328,428.03
5. Step 5: Solve for x
   x = 1,328,428.03/1,320.34
6. Step 6: Final answer
   x = 1,006.13