Finding the Fourth Proportional to 1,561.83, 2,153.57 and 971.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.83 : 2,153.57 = 971.61 : x
2. Step 2: Convert to fraction form
   1,561.83/2,153.57 = 971.61/x
3. Step 3: Cross multiply
   1,561.83x = 2,153.57 × 971.61
4. Step 4: Simplify right side
   1,561.83x = 2,092,425.29
5. Step 5: Solve for x
   x = 2,092,425.29/1,561.83
6. Step 6: Final answer
   x = 1,339.73