Finding the Fourth Proportional to 1,345.05, 1,857.40 and 1,012.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.05 : 1,857.40 = 1,012.90 : x
2. Step 2: Convert to fraction form
   1,345.05/1,857.40 = 1,012.90/x
3. Step 3: Cross multiply
   1,345.05x = 1,857.40 × 1,012.90
4. Step 4: Simplify right side
   1,345.05x = 1,881,360.46
5. Step 5: Solve for x
   x = 1,881,360.46/1,345.05
6. Step 6: Final answer
   x = 1,398.73