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Finding the Fourth Proportional to 266.45, 399.80 and 138.20

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Solution

The fourth proportional to 266.45, 399.80 and 138.20 is: 207.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    266.45 : 399.80 = 138.20 : x
  2. Step 2: Convert to fraction form
    266.45/399.80 = 138.20/x
  3. Step 3: Cross multiply
    266.45x = 399.80 × 138.20
  4. Step 4: Simplify right side
    266.45x = 55,249.67
  5. Step 5: Solve for x
    x = 55,249.67/266.45
  6. Step 6: Final answer
    x = 207.36

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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.