Finding the Fourth Proportional to 1,439.61, 2,158.71 and 561.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.61 : 2,158.71 = 561.48 : x
2. Step 2: Convert to fraction form
   1,439.61/2,158.71 = 561.48/x
3. Step 3: Cross multiply
   1,439.61x = 2,158.71 × 561.48
4. Step 4: Simplify right side
   1,439.61x = 1,212,072.49
5. Step 5: Solve for x
   x = 1,212,072.49/1,439.61
6. Step 6: Final answer
   x = 841.95