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Finding the Fourth Proportional to 768.40, 1,151.40 and 665.20

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Solution

The fourth proportional to 768.40, 1,151.40 and 665.20 is: 996.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.40 : 1,151.40 = 665.20 : x
  2. Step 2: Convert to fraction form
    768.40/1,151.40 = 665.20/x
  3. Step 3: Cross multiply
    768.40x = 1,151.40 × 665.20
  4. Step 4: Simplify right side
    768.40x = 765,911.28
  5. Step 5: Solve for x
    x = 765,911.28/768.40
  6. Step 6: Final answer
    x = 996.76

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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.