Finding the Fourth Proportional to 2,109.72, 3,164.76 and 648.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.72 : 3,164.76 = 648.90 : x
2. Step 2: Convert to fraction form
   2,109.72/3,164.76 = 648.90/x
3. Step 3: Cross multiply
   2,109.72x = 3,164.76 × 648.90
4. Step 4: Simplify right side
   2,109.72x = 2,053,612.76
5. Step 5: Solve for x
   x = 2,053,612.76/2,109.72
6. Step 6: Final answer
   x = 973.41