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Finding the Fourth Proportional to 47.15, 65.05 and 28.72

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Solution

The fourth proportional to 47.15, 65.05 and 28.72 is: 39.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.15 : 65.05 = 28.72 : x
  2. Step 2: Convert to fraction form
    47.15/65.05 = 28.72/x
  3. Step 3: Cross multiply
    47.15x = 65.05 × 28.72
  4. Step 4: Simplify right side
    47.15x = 1,868.24
  5. Step 5: Solve for x
    x = 1,868.24/47.15
  6. Step 6: Final answer
    x = 39.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.