Finding the Fourth Proportional to 1,380.20, 1,905.56 and 988.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.20 : 1,905.56 = 988.52 : x
2. Step 2: Convert to fraction form
   1,380.20/1,905.56 = 988.52/x
3. Step 3: Cross multiply
   1,380.20x = 1,905.56 × 988.52
4. Step 4: Simplify right side
   1,380.20x = 1,883,684.17
5. Step 5: Solve for x
   x = 1,883,684.17/1,380.20
6. Step 6: Final answer
   x = 1,364.79