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Finding the Fourth Proportional to 14.85, 20.47 and 12.90

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Solution

The fourth proportional to 14.85, 20.47 and 12.90 is: 17.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    14.85 : 20.47 = 12.90 : x
  2. Step 2: Convert to fraction form
    14.85/20.47 = 12.90/x
  3. Step 3: Cross multiply
    14.85x = 20.47 × 12.90
  4. Step 4: Simplify right side
    14.85x = 264.06
  5. Step 5: Solve for x
    x = 264.06/14.85
  6. Step 6: Final answer
    x = 17.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.