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Finding the Fourth Proportional to 640.72, 958.84 and 478

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Solution

The fourth proportional to 640.72, 958.84 and 478 is: 715.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.72 : 958.84 = 478 : x
  2. Step 2: Convert to fraction form
    640.72/958.84 = 478/x
  3. Step 3: Cross multiply
    640.72x = 958.84 × 478
  4. Step 4: Simplify right side
    640.72x = 458,325.52
  5. Step 5: Solve for x
    x = 458,325.52/640.72
  6. Step 6: Final answer
    x = 715.33

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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.