Finding the Fourth Proportional to 1,688.76, 2,530.89 and 764.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,688.76 : 2,530.89 = 764.15 : x
2. Step 2: Convert to fraction form
   1,688.76/2,530.89 = 764.15/x
3. Step 3: Cross multiply
   1,688.76x = 2,530.89 × 764.15
4. Step 4: Simplify right side
   1,688.76x = 1,933,966.94
5. Step 5: Solve for x
   x = 1,933,966.94/1,688.76
6. Step 6: Final answer
   x = 1,145.20