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Finding the Fourth Proportional to 645.38, 891.02 and 479.40

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Solution

The fourth proportional to 645.38, 891.02 and 479.40 is: 661.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.38 : 891.02 = 479.40 : x
  2. Step 2: Convert to fraction form
    645.38/891.02 = 479.40/x
  3. Step 3: Cross multiply
    645.38x = 891.02 × 479.40
  4. Step 4: Simplify right side
    645.38x = 427,154.99
  5. Step 5: Solve for x
    x = 427,154.99/645.38
  6. Step 6: Final answer
    x = 661.87

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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.