Finding the Fourth Proportional to 1,390.43, 2,073.86 and 1,172.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.43 : 2,073.86 = 1,172.50 : x
2. Step 2: Convert to fraction form
   1,390.43/2,073.86 = 1,172.50/x
3. Step 3: Cross multiply
   1,390.43x = 2,073.86 × 1,172.50
4. Step 4: Simplify right side
   1,390.43x = 2,431,590.48
5. Step 5: Solve for x
   x = 2,431,590.48/1,390.43
6. Step 6: Final answer
   x = 1,748.80