Finding the Fourth Proportional to 891.83, 1,336.59 and 781.88

Step by Step Solution

1. Step 1: Write the proportion equation
   891.83 : 1,336.59 = 781.88 : x
2. Step 2: Convert to fraction form
   891.83/1,336.59 = 781.88/x
3. Step 3: Cross multiply
   891.83x = 1,336.59 × 781.88
4. Step 4: Simplify right side
   891.83x = 1,045,046.31
5. Step 5: Solve for x
   x = 1,045,046.31/891.83
6. Step 6: Final answer
   x = 1,171.80