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Finding the Fourth Proportional to 20.96, 31.55 and 18.75

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Solution

The fourth proportional to 20.96, 31.55 and 18.75 is: 28.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.96 : 31.55 = 18.75 : x
  2. Step 2: Convert to fraction form
    20.96/31.55 = 18.75/x
  3. Step 3: Cross multiply
    20.96x = 31.55 × 18.75
  4. Step 4: Simplify right side
    20.96x = 591.47
  5. Step 5: Solve for x
    x = 591.47/20.96
  6. Step 6: Final answer
    x = 28.23

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.