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Finding the Fourth Proportional to 509.76, 765.12 and 429.60

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Solution

The fourth proportional to 509.76, 765.12 and 429.60 is: 644.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    509.76 : 765.12 = 429.60 : x
  2. Step 2: Convert to fraction form
    509.76/765.12 = 429.60/x
  3. Step 3: Cross multiply
    509.76x = 765.12 × 429.60
  4. Step 4: Simplify right side
    509.76x = 328,695.55
  5. Step 5: Solve for x
    x = 328,695.55/509.76
  6. Step 6: Final answer
    x = 644.80

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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.