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Finding the Fourth Proportional to 685.94, 1,029.28 and 320.64

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Solution

The fourth proportional to 685.94, 1,029.28 and 320.64 is: 481.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.94 : 1,029.28 = 320.64 : x
  2. Step 2: Convert to fraction form
    685.94/1,029.28 = 320.64/x
  3. Step 3: Cross multiply
    685.94x = 1,029.28 × 320.64
  4. Step 4: Simplify right side
    685.94x = 330,028.34
  5. Step 5: Solve for x
    x = 330,028.34/685.94
  6. Step 6: Final answer
    x = 481.13

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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.