Finding the Fourth Proportional to 1,007.82, 1,390.86 and 615.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.82 : 1,390.86 = 615.06 : x
2. Step 2: Convert to fraction form
   1,007.82/1,390.86 = 615.06/x
3. Step 3: Cross multiply
   1,007.82x = 1,390.86 × 615.06
4. Step 4: Simplify right side
   1,007.82x = 855,462.35
5. Step 5: Solve for x
   x = 855,462.35/1,007.82
6. Step 6: Final answer
   x = 848.82