Finding the Fourth Proportional to 1,356.17, 1,870.16 and 1,020.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,356.17 : 1,870.16 = 1,020.87 : x
2. Step 2: Convert to fraction form
   1,356.17/1,870.16 = 1,020.87/x
3. Step 3: Cross multiply
   1,356.17x = 1,870.16 × 1,020.87
4. Step 4: Simplify right side
   1,356.17x = 1,909,188.96
5. Step 5: Solve for x
   x = 1,909,188.96/1,356.17
6. Step 6: Final answer
   x = 1,407.79