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Finding the Fourth Proportional to 67.78, 101.70 and 31.66

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Solution

The fourth proportional to 67.78, 101.70 and 31.66 is: 47.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.78 : 101.70 = 31.66 : x
  2. Step 2: Convert to fraction form
    67.78/101.70 = 31.66/x
  3. Step 3: Cross multiply
    67.78x = 101.70 × 31.66
  4. Step 4: Simplify right side
    67.78x = 3,219.82
  5. Step 5: Solve for x
    x = 3,219.82/67.78
  6. Step 6: Final answer
    x = 47.50

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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.