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Finding the Fourth Proportional to 685.13, 1,027.28 and 320.15

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Solution

The fourth proportional to 685.13, 1,027.28 and 320.15 is: 480.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.13 : 1,027.28 = 320.15 : x
  2. Step 2: Convert to fraction form
    685.13/1,027.28 = 320.15/x
  3. Step 3: Cross multiply
    685.13x = 1,027.28 × 320.15
  4. Step 4: Simplify right side
    685.13x = 328,887.06
  5. Step 5: Solve for x
    x = 328,887.06/685.13
  6. Step 6: Final answer
    x = 480.04

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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.