Finding the Fourth Proportional to 1,554.50, 2,145.61 and 891.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,554.50 : 2,145.61 = 891.72 : x
2. Step 2: Convert to fraction form
   1,554.50/2,145.61 = 891.72/x
3. Step 3: Cross multiply
   1,554.50x = 2,145.61 × 891.72
4. Step 4: Simplify right side
   1,554.50x = 1,913,272.62
5. Step 5: Solve for x
   x = 1,913,272.62/1,554.50
6. Step 6: Final answer
   x = 1,230.80