Finding the Fourth Proportional to 1,666.78, 2,300.05 and 920.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,666.78 : 2,300.05 = 920.72 : x
2. Step 2: Convert to fraction form
   1,666.78/2,300.05 = 920.72/x
3. Step 3: Cross multiply
   1,666.78x = 2,300.05 × 920.72
4. Step 4: Simplify right side
   1,666.78x = 2,117,690.82
5. Step 5: Solve for x
   x = 2,117,690.82/1,666.78
6. Step 6: Final answer
   x = 1,270.53