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Finding the Fourth Proportional to 513.40, 769.20 and 421.60

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Solution

The fourth proportional to 513.40, 769.20 and 421.60 is: 631.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    513.40 : 769.20 = 421.60 : x
  2. Step 2: Convert to fraction form
    513.40/769.20 = 421.60/x
  3. Step 3: Cross multiply
    513.40x = 769.20 × 421.60
  4. Step 4: Simplify right side
    513.40x = 324,294.72
  5. Step 5: Solve for x
    x = 324,294.72/513.40
  6. Step 6: Final answer
    x = 631.66

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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.