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Finding the Fourth Proportional to 782.13, 1,173.17 and 319.78

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Solution

The fourth proportional to 782.13, 1,173.17 and 319.78 is: 479.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.13 : 1,173.17 = 319.78 : x
  2. Step 2: Convert to fraction form
    782.13/1,173.17 = 319.78/x
  3. Step 3: Cross multiply
    782.13x = 1,173.17 × 319.78
  4. Step 4: Simplify right side
    782.13x = 375,149.64
  5. Step 5: Solve for x
    x = 375,149.64/782.13
  6. Step 6: Final answer
    x = 479.65

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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.