Finding the Fourth Proportional to 1,345.18, 1,856.08 and 770.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.18 : 1,856.08 = 770.20 : x
2. Step 2: Convert to fraction form
   1,345.18/1,856.08 = 770.20/x
3. Step 3: Cross multiply
   1,345.18x = 1,856.08 × 770.20
4. Step 4: Simplify right side
   1,345.18x = 1,429,552.82
5. Step 5: Solve for x
   x = 1,429,552.82/1,345.18
6. Step 6: Final answer
   x = 1,062.72