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Finding the Fourth Proportional to 638.39, 880.96 and 390.13

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Solution

The fourth proportional to 638.39, 880.96 and 390.13 is: 538.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.39 : 880.96 = 390.13 : x
  2. Step 2: Convert to fraction form
    638.39/880.96 = 390.13/x
  3. Step 3: Cross multiply
    638.39x = 880.96 × 390.13
  4. Step 4: Simplify right side
    638.39x = 343,685.75
  5. Step 5: Solve for x
    x = 343,685.75/638.39
  6. Step 6: Final answer
    x = 538.36

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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.