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Finding the Fourth Proportional to 399.68, 551.76 and 289.28

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Solution

The fourth proportional to 399.68, 551.76 and 289.28 is: 399.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.68 : 551.76 = 289.28 : x
  2. Step 2: Convert to fraction form
    399.68/551.76 = 289.28/x
  3. Step 3: Cross multiply
    399.68x = 551.76 × 289.28
  4. Step 4: Simplify right side
    399.68x = 159,613.13
  5. Step 5: Solve for x
    x = 159,613.13/399.68
  6. Step 6: Final answer
    x = 399.35

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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.