Finding the Fourth Proportional to 1,561.65, 2,155.10 and 889.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.65 : 2,155.10 = 889.56 : x
2. Step 2: Convert to fraction form
   1,561.65/2,155.10 = 889.56/x
3. Step 3: Cross multiply
   1,561.65x = 2,155.10 × 889.56
4. Step 4: Simplify right side
   1,561.65x = 1,917,090.76
5. Step 5: Solve for x
   x = 1,917,090.76/1,561.65
6. Step 6: Final answer
   x = 1,227.61