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Finding the Fourth Proportional to 259.80, 389.87 and 138.15

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Solution

The fourth proportional to 259.80, 389.87 and 138.15 is: 207.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.80 : 389.87 = 138.15 : x
  2. Step 2: Convert to fraction form
    259.80/389.87 = 138.15/x
  3. Step 3: Cross multiply
    259.80x = 389.87 × 138.15
  4. Step 4: Simplify right side
    259.80x = 53,861.69
  5. Step 5: Solve for x
    x = 53,861.69/259.80
  6. Step 6: Final answer
    x = 207.32

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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.