Finding the Fourth Proportional to 1,109.88, 1,531.80 and 667.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.88 : 1,531.80 = 667.98 : x
2. Step 2: Convert to fraction form
   1,109.88/1,531.80 = 667.98/x
3. Step 3: Cross multiply
   1,109.88x = 1,531.80 × 667.98
4. Step 4: Simplify right side
   1,109.88x = 1,023,211.76
5. Step 5: Solve for x
   x = 1,023,211.76/1,109.88
6. Step 6: Final answer
   x = 921.91