Finding the Fourth Proportional to 1,315.15, 1,814.58 and 783.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.15 : 1,814.58 = 783.69 : x
2. Step 2: Convert to fraction form
   1,315.15/1,814.58 = 783.69/x
3. Step 3: Cross multiply
   1,315.15x = 1,814.58 × 783.69
4. Step 4: Simplify right side
   1,315.15x = 1,422,068.82
5. Step 5: Solve for x
   x = 1,422,068.82/1,315.15
6. Step 6: Final answer
   x = 1,081.30