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Finding the Fourth Proportional to 61.35, 91.81 and 47.78

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Solution

The fourth proportional to 61.35, 91.81 and 47.78 is: 71.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.35 : 91.81 = 47.78 : x
  2. Step 2: Convert to fraction form
    61.35/91.81 = 47.78/x
  3. Step 3: Cross multiply
    61.35x = 91.81 × 47.78
  4. Step 4: Simplify right side
    61.35x = 4,386.68
  5. Step 5: Solve for x
    x = 4,386.68/61.35
  6. Step 6: Final answer
    x = 71.50

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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.