Finding the Fourth Proportional to 1,603.76, 2,213.24 and 931.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,603.76 : 2,213.24 = 931.50 : x
2. Step 2: Convert to fraction form
   1,603.76/2,213.24 = 931.50/x
3. Step 3: Cross multiply
   1,603.76x = 2,213.24 × 931.50
4. Step 4: Simplify right side
   1,603.76x = 2,061,628.40
5. Step 5: Solve for x
   x = 2,061,628.40/1,603.76
6. Step 6: Final answer
   x = 1,285.50