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Finding the Fourth Proportional to 509.76, 765 and 221.28

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Solution

The fourth proportional to 509.76, 765 and 221.28 is: 332.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    509.76 : 765 = 221.28 : x
  2. Step 2: Convert to fraction form
    509.76/765 = 221.28/x
  3. Step 3: Cross multiply
    509.76x = 765 × 221.28
  4. Step 4: Simplify right side
    509.76x = 169,279.20
  5. Step 5: Solve for x
    x = 169,279.20/509.76
  6. Step 6: Final answer
    x = 332.08

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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.