Finding the Fourth Proportional to 1,061.28, 1,587.76 and 788

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.28 : 1,587.76 = 788 : x
2. Step 2: Convert to fraction form
   1,061.28/1,587.76 = 788/x
3. Step 3: Cross multiply
   1,061.28x = 1,587.76 × 788
4. Step 4: Simplify right side
   1,061.28x = 1,251,154.88
5. Step 5: Solve for x
   x = 1,251,154.88/1,061.28
6. Step 6: Final answer
   x = 1,178.91