Finding the Fourth Proportional to 1,386.44, 1,914.18 and 1,071.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.44 : 1,914.18 = 1,071.15 : x
2. Step 2: Convert to fraction form
   1,386.44/1,914.18 = 1,071.15/x
3. Step 3: Cross multiply
   1,386.44x = 1,914.18 × 1,071.15
4. Step 4: Simplify right side
   1,386.44x = 2,050,373.91
5. Step 5: Solve for x
   x = 2,050,373.91/1,386.44
6. Step 6: Final answer
   x = 1,478.88