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Finding the Fourth Proportional to 39.17, 58.70 and 20.87

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Solution

The fourth proportional to 39.17, 58.70 and 20.87 is: 31.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.17 : 58.70 = 20.87 : x
  2. Step 2: Convert to fraction form
    39.17/58.70 = 20.87/x
  3. Step 3: Cross multiply
    39.17x = 58.70 × 20.87
  4. Step 4: Simplify right side
    39.17x = 1,225.07
  5. Step 5: Solve for x
    x = 1,225.07/39.17
  6. Step 6: Final answer
    x = 31.28

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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.