Finding the Fourth Proportional to 1,378.13, 1,899.80 and 1,129.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.13 : 1,899.80 = 1,129.06 : x
2. Step 2: Convert to fraction form
   1,378.13/1,899.80 = 1,129.06/x
3. Step 3: Cross multiply
   1,378.13x = 1,899.80 × 1,129.06
4. Step 4: Simplify right side
   1,378.13x = 2,144,978.69
5. Step 5: Solve for x
   x = 2,144,978.69/1,378.13
6. Step 6: Final answer
   x = 1,556.44