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Finding the Fourth Proportional to 412.21, 618.30 and 138.30

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Solution

The fourth proportional to 412.21, 618.30 and 138.30 is: 207.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    412.21 : 618.30 = 138.30 : x
  2. Step 2: Convert to fraction form
    412.21/618.30 = 138.30/x
  3. Step 3: Cross multiply
    412.21x = 618.30 × 138.30
  4. Step 4: Simplify right side
    412.21x = 85,511.91
  5. Step 5: Solve for x
    x = 85,511.91/412.21
  6. Step 6: Final answer
    x = 207.45

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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.