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Finding the Fourth Proportional to 47.31, 70.64 and 42.18

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Solution

The fourth proportional to 47.31, 70.64 and 42.18 is: 62.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.31 : 70.64 = 42.18 : x
  2. Step 2: Convert to fraction form
    47.31/70.64 = 42.18/x
  3. Step 3: Cross multiply
    47.31x = 70.64 × 42.18
  4. Step 4: Simplify right side
    47.31x = 2,979.38
  5. Step 5: Solve for x
    x = 2,979.38/47.31
  6. Step 6: Final answer
    x = 62.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.