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Finding the Fourth Proportional to 685.80, 1,027.86 and 320.16

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Solution

The fourth proportional to 685.80, 1,027.86 and 320.16 is: 479.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.80 : 1,027.86 = 320.16 : x
  2. Step 2: Convert to fraction form
    685.80/1,027.86 = 320.16/x
  3. Step 3: Cross multiply
    685.80x = 1,027.86 × 320.16
  4. Step 4: Simplify right side
    685.80x = 329,079.66
  5. Step 5: Solve for x
    x = 329,079.66/685.80
  6. Step 6: Final answer
    x = 479.85

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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.