Finding the Fourth Proportional to 981.78, 1,475.31 and 919.50

Step by Step Solution

1. Step 1: Write the proportion equation
   981.78 : 1,475.31 = 919.50 : x
2. Step 2: Convert to fraction form
   981.78/1,475.31 = 919.50/x
3. Step 3: Cross multiply
   981.78x = 1,475.31 × 919.50
4. Step 4: Simplify right side
   981.78x = 1,356,547.55
5. Step 5: Solve for x
   x = 1,356,547.55/981.78
6. Step 6: Final answer
   x = 1,381.72