Finding the Fourth Proportional to 1,056.64, 1,457.86 and 636.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,056.64 : 1,457.86 = 636.79 : x
2. Step 2: Convert to fraction form
   1,056.64/1,457.86 = 636.79/x
3. Step 3: Cross multiply
   1,056.64x = 1,457.86 × 636.79
4. Step 4: Simplify right side
   1,056.64x = 928,350.67
5. Step 5: Solve for x
   x = 928,350.67/1,056.64
6. Step 6: Final answer
   x = 878.59