Finding the Fourth Proportional to 1,561.55, 2,338.91 and 1,212.17

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.55 : 2,338.91 = 1,212.17 : x
2. Step 2: Convert to fraction form
   1,561.55/2,338.91 = 1,212.17/x
3. Step 3: Cross multiply
   1,561.55x = 2,338.91 × 1,212.17
4. Step 4: Simplify right side
   1,561.55x = 2,835,143.32
5. Step 5: Solve for x
   x = 2,835,143.32/1,561.55
6. Step 6: Final answer
   x = 1,815.60