Finding the Fourth Proportional to 1,388.32, 2,081.86 and 763.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.32 : 2,081.86 = 763.20 : x
2. Step 2: Convert to fraction form
   1,388.32/2,081.86 = 763.20/x
3. Step 3: Cross multiply
   1,388.32x = 2,081.86 × 763.20
4. Step 4: Simplify right side
   1,388.32x = 1,588,875.55
5. Step 5: Solve for x
   x = 1,588,875.55/1,388.32
6. Step 6: Final answer
   x = 1,144.46