Finding the Fourth Proportional to 1,008.55, 1,390.37 and 784.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.55 : 1,390.37 = 784.79 : x
2. Step 2: Convert to fraction form
   1,008.55/1,390.37 = 784.79/x
3. Step 3: Cross multiply
   1,008.55x = 1,390.37 × 784.79
4. Step 4: Simplify right side
   1,008.55x = 1,091,142.81
5. Step 5: Solve for x
   x = 1,091,142.81/1,008.55
6. Step 6: Final answer
   x = 1,081.89