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Finding the Fourth Proportional to 20.90, 31.36 and 16.40

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Solution

The fourth proportional to 20.90, 31.36 and 16.40 is: 24.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.90 : 31.36 = 16.40 : x
  2. Step 2: Convert to fraction form
    20.90/31.36 = 16.40/x
  3. Step 3: Cross multiply
    20.90x = 31.36 × 16.40
  4. Step 4: Simplify right side
    20.90x = 514.30
  5. Step 5: Solve for x
    x = 514.30/20.90
  6. Step 6: Final answer
    x = 24.61

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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.