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Finding the Fourth Proportional to 47.80, 71.60 and 39.72

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Solution

The fourth proportional to 47.80, 71.60 and 39.72 is: 59.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.80 : 71.60 = 39.72 : x
  2. Step 2: Convert to fraction form
    47.80/71.60 = 39.72/x
  3. Step 3: Cross multiply
    47.80x = 71.60 × 39.72
  4. Step 4: Simplify right side
    47.80x = 2,843.95
  5. Step 5: Solve for x
    x = 2,843.95/47.80
  6. Step 6: Final answer
    x = 59.50

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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.