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Finding the Fourth Proportional to 39.80, 59.65 and 21.75

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Solution

The fourth proportional to 39.80, 59.65 and 21.75 is: 32.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.80 : 59.65 = 21.75 : x
  2. Step 2: Convert to fraction form
    39.80/59.65 = 21.75/x
  3. Step 3: Cross multiply
    39.80x = 59.65 × 21.75
  4. Step 4: Simplify right side
    39.80x = 1,297.39
  5. Step 5: Solve for x
    x = 1,297.39/39.80
  6. Step 6: Final answer
    x = 32.60

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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.