Finding the Fourth Proportional to 1,512.21, 2,085.79 and 1,388.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,512.21 : 2,085.79 = 1,388.28 : x
2. Step 2: Convert to fraction form
   1,512.21/2,085.79 = 1,388.28/x
3. Step 3: Cross multiply
   1,512.21x = 2,085.79 × 1,388.28
4. Step 4: Simplify right side
   1,512.21x = 2,895,667.50
5. Step 5: Solve for x
   x = 2,895,667.50/1,512.21
6. Step 6: Final answer
   x = 1,914.85