Finding the Fourth Proportional to 1,090.88, 1,506.72 and 781.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,090.88 : 1,506.72 = 781.76 : x
2. Step 2: Convert to fraction form
   1,090.88/1,506.72 = 781.76/x
3. Step 3: Cross multiply
   1,090.88x = 1,506.72 × 781.76
4. Step 4: Simplify right side
   1,090.88x = 1,177,893.43
5. Step 5: Solve for x
   x = 1,177,893.43/1,090.88
6. Step 6: Final answer
   x = 1,079.76