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Finding the Fourth Proportional to 685.64, 1,028.74 and 320.44

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Solution

The fourth proportional to 685.64, 1,028.74 and 320.44 is: 480.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.64 : 1,028.74 = 320.44 : x
  2. Step 2: Convert to fraction form
    685.64/1,028.74 = 320.44/x
  3. Step 3: Cross multiply
    685.64x = 1,028.74 × 320.44
  4. Step 4: Simplify right side
    685.64x = 329,649.45
  5. Step 5: Solve for x
    x = 329,649.45/685.64
  6. Step 6: Final answer
    x = 480.79

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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.