Finding the Fourth Proportional to 1,407.76, 2,112.24 and 790.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.76 : 2,112.24 = 790.72 : x
2. Step 2: Convert to fraction form
   1,407.76/2,112.24 = 790.72/x
3. Step 3: Cross multiply
   1,407.76x = 2,112.24 × 790.72
4. Step 4: Simplify right side
   1,407.76x = 1,670,190.41
5. Step 5: Solve for x
   x = 1,670,190.41/1,407.76
6. Step 6: Final answer
   x = 1,186.42