Finding the Fourth Proportional to 978,256.28, 1,349,421.72 and 615,105.20

Step by Step Solution

1. Step 1: Write the proportion equation
   978,256.28 : 1,349,421.72 = 615,105.20 : x
2. Step 2: Convert to fraction form
   978,256.28/1,349,421.72 = 615,105.20/x
3. Step 3: Cross multiply
   978,256.28x = 1,349,421.72 × 615,105.20
4. Step 4: Simplify right side
   978,256.28x = 830,036,316,964.94
5. Step 5: Solve for x
   x = 830,036,316,964.94/978,256.28
6. Step 6: Final answer
   x = 848,485.55