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Finding the Fourth Proportional to 424.60, 638.44 and 390.77

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Solution

The fourth proportional to 424.60, 638.44 and 390.77 is: 587.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    424.60 : 638.44 = 390.77 : x
  2. Step 2: Convert to fraction form
    424.60/638.44 = 390.77/x
  3. Step 3: Cross multiply
    424.60x = 638.44 × 390.77
  4. Step 4: Simplify right side
    424.60x = 249,479.03
  5. Step 5: Solve for x
    x = 249,479.03/424.60
  6. Step 6: Final answer
    x = 587.57

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.