Finding the Fourth Proportional to 1,215.30, 1,818.15 and 1,100.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,215.30 : 1,818.15 = 1,100.10 : x
2. Step 2: Convert to fraction form
   1,215.30/1,818.15 = 1,100.10/x
3. Step 3: Cross multiply
   1,215.30x = 1,818.15 × 1,100.10
4. Step 4: Simplify right side
   1,215.30x = 2,000,146.82
5. Step 5: Solve for x
   x = 2,000,146.82/1,215.30
6. Step 6: Final answer
   x = 1,645.80