Finding the Fourth Proportional to 1,388.56, 1,914.92 and 947.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.56 : 1,914.92 = 947.12 : x
2. Step 2: Convert to fraction form
   1,388.56/1,914.92 = 947.12/x
3. Step 3: Cross multiply
   1,388.56x = 1,914.92 × 947.12
4. Step 4: Simplify right side
   1,388.56x = 1,813,659.03
5. Step 5: Solve for x
   x = 1,813,659.03/1,388.56
6. Step 6: Final answer
   x = 1,306.14