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Finding the Fourth Proportional to 768, 1,151.31 and 280.95

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Solution

The fourth proportional to 768, 1,151.31 and 280.95 is: 421.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    768 : 1,151.31 = 280.95 : x
  2. Step 2: Convert to fraction form
    768/1,151.31 = 280.95/x
  3. Step 3: Cross multiply
    768x = 1,151.31 × 280.95
  4. Step 4: Simplify right side
    768x = 323,460.54
  5. Step 5: Solve for x
    x = 323,460.54/768
  6. Step 6: Final answer
    x = 421.17

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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.