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Finding the Fourth Proportional to 640.96, 885.12 and 407.68

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Solution

The fourth proportional to 640.96, 885.12 and 407.68 is: 562.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.96 : 885.12 = 407.68 : x
  2. Step 2: Convert to fraction form
    640.96/885.12 = 407.68/x
  3. Step 3: Cross multiply
    640.96x = 885.12 × 407.68
  4. Step 4: Simplify right side
    640.96x = 360,845.72
  5. Step 5: Solve for x
    x = 360,845.72/640.96
  6. Step 6: Final answer
    x = 562.98

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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.