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Finding the Fourth Proportional to 768.16, 1,151.28 and 280.80

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Solution

The fourth proportional to 768.16, 1,151.28 and 280.80 is: 420.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.16 : 1,151.28 = 280.80 : x
  2. Step 2: Convert to fraction form
    768.16/1,151.28 = 280.80/x
  3. Step 3: Cross multiply
    768.16x = 1,151.28 × 280.80
  4. Step 4: Simplify right side
    768.16x = 323,279.42
  5. Step 5: Solve for x
    x = 323,279.42/768.16
  6. Step 6: Final answer
    x = 420.85

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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.