Finding the Fourth Proportional to 1,005.40, 1,512.15 and 900.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.40 : 1,512.15 = 900.10 : x
2. Step 2: Convert to fraction form
   1,005.40/1,512.15 = 900.10/x
3. Step 3: Cross multiply
   1,005.40x = 1,512.15 × 900.10
4. Step 4: Simplify right side
   1,005.40x = 1,361,086.22
5. Step 5: Solve for x
   x = 1,361,086.22/1,005.40
6. Step 6: Final answer
   x = 1,353.78