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Finding the Fourth Proportional to 412.15, 618.16 and 138.21

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Solution

The fourth proportional to 412.15, 618.16 and 138.21 is: 207.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    412.15 : 618.16 = 138.21 : x
  2. Step 2: Convert to fraction form
    412.15/618.16 = 138.21/x
  3. Step 3: Cross multiply
    412.15x = 618.16 × 138.21
  4. Step 4: Simplify right side
    412.15x = 85,435.89
  5. Step 5: Solve for x
    x = 85,435.89/412.15
  6. Step 6: Final answer
    x = 207.29

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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.