Finding the Fourth Proportional to 1,290.34, 1,779.86 and 766

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.34 : 1,779.86 = 766 : x
2. Step 2: Convert to fraction form
   1,290.34/1,779.86 = 766/x
3. Step 3: Cross multiply
   1,290.34x = 1,779.86 × 766
4. Step 4: Simplify right side
   1,290.34x = 1,363,372.76
5. Step 5: Solve for x
   x = 1,363,372.76/1,290.34
6. Step 6: Final answer
   x = 1,056.60