Finding the Fourth Proportional to 1,405.90, 2,109.30 and 711.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.90 : 2,109.30 = 711.96 : x
2. Step 2: Convert to fraction form
   1,405.90/2,109.30 = 711.96/x
3. Step 3: Cross multiply
   1,405.90x = 2,109.30 × 711.96
4. Step 4: Simplify right side
   1,405.90x = 1,501,737.23
5. Step 5: Solve for x
   x = 1,501,737.23/1,405.90
6. Step 6: Final answer
   x = 1,068.17