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Finding the Fourth Proportional to 21.37, 31.99 and 13.75

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Solution

The fourth proportional to 21.37, 31.99 and 13.75 is: 20.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.37 : 31.99 = 13.75 : x
  2. Step 2: Convert to fraction form
    21.37/31.99 = 13.75/x
  3. Step 3: Cross multiply
    21.37x = 31.99 × 13.75
  4. Step 4: Simplify right side
    21.37x = 439.86
  5. Step 5: Solve for x
    x = 439.86/21.37
  6. Step 6: Final answer
    x = 20.58

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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.