Finding the Fourth Proportional to 1,512.50, 2,087.15 and 840.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,512.50 : 2,087.15 = 840.30 : x
2. Step 2: Convert to fraction form
   1,512.50/2,087.15 = 840.30/x
3. Step 3: Cross multiply
   1,512.50x = 2,087.15 × 840.30
4. Step 4: Simplify right side
   1,512.50x = 1,753,832.15
5. Step 5: Solve for x
   x = 1,753,832.15/1,512.50
6. Step 6: Final answer
   x = 1,159.56