Finding the Fourth Proportional to 1,287.48, 1,776.69 and 763.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.48 : 1,776.69 = 763.50 : x
2. Step 2: Convert to fraction form
   1,287.48/1,776.69 = 763.50/x
3. Step 3: Cross multiply
   1,287.48x = 1,776.69 × 763.50
4. Step 4: Simplify right side
   1,287.48x = 1,356,502.82
5. Step 5: Solve for x
   x = 1,356,502.82/1,287.48
6. Step 6: Final answer
   x = 1,053.61