Finding the Fourth Proportional to 1,387.32, 1,914.69 and 891.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.32 : 1,914.69 = 891.37 : x
2. Step 2: Convert to fraction form
   1,387.32/1,914.69 = 891.37/x
3. Step 3: Cross multiply
   1,387.32x = 1,914.69 × 891.37
4. Step 4: Simplify right side
   1,387.32x = 1,706,697.23
5. Step 5: Solve for x
   x = 1,706,697.23/1,387.32
6. Step 6: Final answer
   x = 1,230.21