Finding the Fourth Proportional to 1,390.50, 2,086.47 and 706.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.50 : 2,086.47 = 706.50 : x
2. Step 2: Convert to fraction form
   1,390.50/2,086.47 = 706.50/x
3. Step 3: Cross multiply
   1,390.50x = 2,086.47 × 706.50
4. Step 4: Simplify right side
   1,390.50x = 1,474,091.06
5. Step 5: Solve for x
   x = 1,474,091.06/1,390.50
6. Step 6: Final answer
   x = 1,060.12