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Finding the Fourth Proportional to 432.40, 648.60 and 385.60

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Solution

The fourth proportional to 432.40, 648.60 and 385.60 is: 578.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.40 : 648.60 = 385.60 : x
  2. Step 2: Convert to fraction form
    432.40/648.60 = 385.60/x
  3. Step 3: Cross multiply
    432.40x = 648.60 × 385.60
  4. Step 4: Simplify right side
    432.40x = 250,100.16
  5. Step 5: Solve for x
    x = 250,100.16/432.40
  6. Step 6: Final answer
    x = 578.40

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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.