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Finding the Fourth Proportional to 685.12, 1,027.72 and 412.96

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Solution

The fourth proportional to 685.12, 1,027.72 and 412.96 is: 619.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.12 : 1,027.72 = 412.96 : x
  2. Step 2: Convert to fraction form
    685.12/1,027.72 = 412.96/x
  3. Step 3: Cross multiply
    685.12x = 1,027.72 × 412.96
  4. Step 4: Simplify right side
    685.12x = 424,407.25
  5. Step 5: Solve for x
    x = 424,407.25/685.12
  6. Step 6: Final answer
    x = 619.46

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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.