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Finding the Fourth Proportional to 686.32, 1,028.74 and 320.80

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Solution

The fourth proportional to 686.32, 1,028.74 and 320.80 is: 480.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.32 : 1,028.74 = 320.80 : x
  2. Step 2: Convert to fraction form
    686.32/1,028.74 = 320.80/x
  3. Step 3: Cross multiply
    686.32x = 1,028.74 × 320.80
  4. Step 4: Simplify right side
    686.32x = 330,019.79
  5. Step 5: Solve for x
    x = 330,019.79/686.32
  6. Step 6: Final answer
    x = 480.85

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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.