Finding the Fourth Proportional to 3,460.78, 5,190.90 and 1,120.69

Step by Step Solution

1. Step 1: Write the proportion equation
   3,460.78 : 5,190.90 = 1,120.69 : x
2. Step 2: Convert to fraction form
   3,460.78/5,190.90 = 1,120.69/x
3. Step 3: Cross multiply
   3,460.78x = 5,190.90 × 1,120.69
4. Step 4: Simplify right side
   3,460.78x = 5,817,389.72
5. Step 5: Solve for x
   x = 5,817,389.72/3,460.78
6. Step 6: Final answer
   x = 1,680.95