Finding the Fourth Proportional to 1,026.81, 1,538.06 and 853.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,026.81 : 1,538.06 = 853.07 : x
2. Step 2: Convert to fraction form
   1,026.81/1,538.06 = 853.07/x
3. Step 3: Cross multiply
   1,026.81x = 1,538.06 × 853.07
4. Step 4: Simplify right side
   1,026.81x = 1,312,060.89
5. Step 5: Solve for x
   x = 1,312,060.89/1,026.81
6. Step 6: Final answer
   x = 1,277.80