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Finding the Fourth Proportional to 39.80, 59.70 and 28.48

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Solution

The fourth proportional to 39.80, 59.70 and 28.48 is: 42.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.80 : 59.70 = 28.48 : x
  2. Step 2: Convert to fraction form
    39.80/59.70 = 28.48/x
  3. Step 3: Cross multiply
    39.80x = 59.70 × 28.48
  4. Step 4: Simplify right side
    39.80x = 1,700.11
  5. Step 5: Solve for x
    x = 1,700.11/39.80
  6. Step 6: Final answer
    x = 42.71

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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.