Finding the Fourth Proportional to 1,002.21, 1,380.02 and 791.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,002.21 : 1,380.02 = 791.71 : x
2. Step 2: Convert to fraction form
   1,002.21/1,380.02 = 791.71/x
3. Step 3: Cross multiply
   1,002.21x = 1,380.02 × 791.71
4. Step 4: Simplify right side
   1,002.21x = 1,092,575.63
5. Step 5: Solve for x
   x = 1,092,575.63/1,002.21
6. Step 6: Final answer
   x = 1,090.17