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Finding the Fourth Proportional to 43.40, 65.10 and 20.57

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Solution

The fourth proportional to 43.40, 65.10 and 20.57 is: 30.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    43.40 : 65.10 = 20.57 : x
  2. Step 2: Convert to fraction form
    43.40/65.10 = 20.57/x
  3. Step 3: Cross multiply
    43.40x = 65.10 × 20.57
  4. Step 4: Simplify right side
    43.40x = 1,338.78
  5. Step 5: Solve for x
    x = 1,338.78/43.40
  6. Step 6: Final answer
    x = 30.85

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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.