Finding the Fourth Proportional to 1,438.68, 1,987.20 and 1,111.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,438.68 : 1,987.20 = 1,111.16 : x
2. Step 2: Convert to fraction form
   1,438.68/1,987.20 = 1,111.16/x
3. Step 3: Cross multiply
   1,438.68x = 1,987.20 × 1,111.16
4. Step 4: Simplify right side
   1,438.68x = 2,208,097.15
5. Step 5: Solve for x
   x = 2,208,097.15/1,438.68
6. Step 6: Final answer
   x = 1,534.81