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Finding the Fourth Proportional to 478.40, 659.04 and 399.68

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Solution

The fourth proportional to 478.40, 659.04 and 399.68 is: 550.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.40 : 659.04 = 399.68 : x
  2. Step 2: Convert to fraction form
    478.40/659.04 = 399.68/x
  3. Step 3: Cross multiply
    478.40x = 659.04 × 399.68
  4. Step 4: Simplify right side
    478.40x = 263,405.11
  5. Step 5: Solve for x
    x = 263,405.11/478.40
  6. Step 6: Final answer
    x = 550.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.