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Finding the Fourth Proportional to 412.55, 618.85 and 138.53

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Solution

The fourth proportional to 412.55, 618.85 and 138.53 is: 207.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    412.55 : 618.85 = 138.53 : x
  2. Step 2: Convert to fraction form
    412.55/618.85 = 138.53/x
  3. Step 3: Cross multiply
    412.55x = 618.85 × 138.53
  4. Step 4: Simplify right side
    412.55x = 85,725.85
  5. Step 5: Solve for x
    x = 85,725.85/412.55
  6. Step 6: Final answer
    x = 207.80

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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.