Finding the Fourth Proportional to 1,339.72, 2,010.88 and 646.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.72 : 2,010.88 = 646.88 : x
2. Step 2: Convert to fraction form
   1,339.72/2,010.88 = 646.88/x
3. Step 3: Cross multiply
   1,339.72x = 2,010.88 × 646.88
4. Step 4: Simplify right side
   1,339.72x = 1,300,788.81
5. Step 5: Solve for x
   x = 1,300,788.81/1,339.72
6. Step 6: Final answer
   x = 970.94