Finding the Fourth Proportional to 1,528.40, 2,109.23 and 938.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,528.40 : 2,109.23 = 938.72 : x
2. Step 2: Convert to fraction form
   1,528.40/2,109.23 = 938.72/x
3. Step 3: Cross multiply
   1,528.40x = 2,109.23 × 938.72
4. Step 4: Simplify right side
   1,528.40x = 1,979,961.15
5. Step 5: Solve for x
   x = 1,979,961.15/1,528.40
6. Step 6: Final answer
   x = 1,295.45