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Finding the Fourth Proportional to 765.79, 1,149.12 and 278.78

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Solution

The fourth proportional to 765.79, 1,149.12 and 278.78 is: 418.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.79 : 1,149.12 = 278.78 : x
  2. Step 2: Convert to fraction form
    765.79/1,149.12 = 278.78/x
  3. Step 3: Cross multiply
    765.79x = 1,149.12 × 278.78
  4. Step 4: Simplify right side
    765.79x = 320,345.93
  5. Step 5: Solve for x
    x = 320,345.93/765.79
  6. Step 6: Final answer
    x = 418.32

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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.