Finding the Fourth Proportional to 1,379.72, 2,059.47 and 1,215.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.72 : 2,059.47 = 1,215.69 : x
2. Step 2: Convert to fraction form
   1,379.72/2,059.47 = 1,215.69/x
3. Step 3: Cross multiply
   1,379.72x = 2,059.47 × 1,215.69
4. Step 4: Simplify right side
   1,379.72x = 2,503,677.08
5. Step 5: Solve for x
   x = 2,503,677.08/1,379.72
6. Step 6: Final answer
   x = 1,814.63