Finding the Fourth Proportional to 1,086.61, 1,499.40 and 666.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.61 : 1,499.40 = 666.98 : x
2. Step 2: Convert to fraction form
   1,086.61/1,499.40 = 666.98/x
3. Step 3: Cross multiply
   1,086.61x = 1,499.40 × 666.98
4. Step 4: Simplify right side
   1,086.61x = 1,000,064.82
5. Step 5: Solve for x
   x = 1,000,064.82/1,086.61
6. Step 6: Final answer
   x = 920.36