Finding the Fourth Proportional to 1,620.72, 2,430.72 and 971.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620.72 : 2,430.72 = 971.28 : x
2. Step 2: Convert to fraction form
   1,620.72/2,430.72 = 971.28/x
3. Step 3: Cross multiply
   1,620.72x = 2,430.72 × 971.28
4. Step 4: Simplify right side
   1,620.72x = 2,360,909.72
5. Step 5: Solve for x
   x = 2,360,909.72/1,620.72
6. Step 6: Final answer
   x = 1,456.70