Finding the Fourth Proportional to 1,056.32, 1,457.76 and 636.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.32 : 1,457.76 = 636.80 : x
2. Step 2: Convert to fraction form
   1,056.32/1,457.76 = 636.80/x
3. Step 3: Cross multiply
   1,056.32x = 1,457.76 × 636.80
4. Step 4: Simplify right side
   1,056.32x = 928,301.57
5. Step 5: Solve for x
   x = 928,301.57/1,056.32
6. Step 6: Final answer
   x = 878.81